TEM8 antibodies and their use in treatment and detection of tumors

ABSTRACT

Antibodies that specifically bind TEM8 protein, conjugates thereof, and their use, are disclosed herein. In some examples the conjugates and antibodies are useful for methods of detecting and treating pathogenic angiogenesis. In other examples the conjugates and antibodies are useful for methods of detecting and treating cancer. In additional examples, the conjugates and antibodies are useful for methods of decreasing binding of Anthrax protective antigen to a cell.

CROSS REFERENCE TO RELATED APPLICATIONS

This is the U.S. National Stage of International Application No.PCT/US2014/060299, filed Oct. 13, 2014, which was published in Englishunder PCT Article 21(2), which in turn claims the benefit of U.S.Provisional Application No. 61/889,958, filed Oct. 11, 2013. Theprovisional application is incorporated by reference herein in itsentirety.

PARTIES TO A JOINT RESEARCH AGREEMENT

This invention was made under Public Health Service Cooperative Researchand Development Agreement (PHS-CRADA) No. 02744 between the NationalInstitutes of Health National Cancer Institute and Biomed ValleyDiscoveries, Inc.

FIELD OF THE DISCLOSURE

This application relates to the field of cancer, particularly toantibodies, antigen binding fragments, and conjugates, that specificallybind TEM8 and their use.

BACKGROUND

Angiogenesis, the process of developing a hemovascular network frompre-existing blood vessels, is essential for the growth of solid tumorsand is a component of normal wound healing and growth processes. It alsohas been implicated in the pathophysiology of many diseases andconditions, including atherogenesis, arthritis, psoriasis, cornealneo-vascularization, and diabetic retinopathy. Angiogenesis factors playan important role in the development of malignancies.

Tumor Endothelial Marker 8 (TEM8), also known as Anthrax Toxin Receptor1 (ANTXR1), is a single pass, cell surface glycoprotein originallyidentified, along with a number of other unrelated Tumor EndothelialMarkers, based on its over-expression in the endothelial cells that linethe tumor vasculature of human colorectal cancer. TEM8 also functions asa cell surface receptor for Anthrax toxin, and shares 58% amino acididentity with CMG2 (also known as ANTXR2), a second receptor for Anthraxtoxin protein. Unlike VEGF, VEGFRs, and many other key angiogenesisregulators, TEM8 is not required for developmental angiogenesis, woundhealing or normal physiological angiogenesis of the corpus luteum. TEM8is up-regulated on tumor vessels of various tumor types in both mice andhumans, and, in some tumors, is also expressed by the tumor cells. Aneed exists for chemotherapeutic agents that target TEM8, and for highaffinity antibodies that specifically bind TEM8 on the cell surface.

SUMMARY

Isolated human monoclonal neutralizing antibodies that specifically bindto TEM8 on the cell surface, antigen binding fragments of suchantibodies, conjugates thereof, chimeric antigen receptor (CAR) T cellsexpressing a CAR including an extracellular domain including a disclosedantibody or antigen binding fragment thereof, and methods of using thesemolecules, are provided. In some embodiments, the conjugates include aneffector molecule or detectable marker covalently linked to a monoclonalantibody, or an antigen binding fragment thereof, that specificallybinds TEM8. In some embodiments, the antibodies or conjugates are usedin methods for the detection of an endothelial cell from a subject thatexpresses TEM8. In some embodiments, detection of an endothelial cellfrom a subject that expresses TEM8 detects pathological angiogenesis ina subject. In other embodiments, the antibodies and conjugates are usedin methods of detecting and/or treating a tumor, for example acarcinoma. In still other embodiments, the antibodies and conjugates areused in methods of decreasing Anthrax protective antigen (PA) binding toa cell.

It will be understood that the antibodies, conjugates, and CAR T cellsand methods of their use are useful beyond the specific circumstancesthat are described in detail herein. For instance, the methods areexpected to be useful for a variety of situations, for example to detectan endothelial cell expressing TEM8 in a subject, treat a tumor in asubject or to decrease binding of Anthrax PA to a cell.

The foregoing and features and advantages of the disclosure will becomemore apparent from the following detailed description, which proceedswith reference to the accompanying figures.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1A and 1B are a series of graphs illustrating the results of flowcytometry assays of the binding of human TEM8 antibodies m825, m822,m830, and m863 to cells expressing TEM8 or CMG2. CMG2 is the closesthuman homologue of TEM8.

FIG. 2 shows a series of digital images illustrating immunofluorescentstaining of tumor vessels using m825 antibody in a human IgG1 format.Wildtype (WT) and TEM8 knockout (TEM8 KO) mice were inoculated withDLD-1 colon cancer cells subcutaneously. After formation of thexenograft tumor, a sample from the tumor was obtained and stained withCD31 antibody (specific for blood vessels) and the m825 antibody(specific for TEM8). The m825 antibody stained the DLD-1 tumor vesselsby immunofluorescence.

FIG. 3 is a graph illustrating inhibition of the growth of UACC melanomacell xenografts by the m825 antibody in athymic nude mice. Mice wereinoculated with UACC melanoma cells subcutaneously, and m825 antibody,control IgG, or control vehicle, were administered to the mice at a doseof 20 or 40 mg/Kg on each of the days indicated by an arrow on thegraph.

FIG. 4 is a graph illustrating that the m825 antibody inhibits thegrowth of HCT116 colon cancer cell xenografts grown subcutaneously inathymic nude mice. Mice were inoculated with HCT116 colon cancer cellssubcutaneously, and m825 antibody, control IgG, or control vehicle, wereadministered to the mice at a dose of 15 mg/Kg on each of the daysindicated by an arrow on the graph.

FIG. 5 is a graph illustrating inhibition of the growth of UACC melanomacell xenografts grown subcutaneously in athymic nude mice by anti-TEM8antibodies. Mice were inoculated with UACC melanoma cellssubcutaneously, and the m825, m822, m830, and m863 antibodies in fullyhuman IgG1 format were administered three time a week to the mice at adose of 15 mg/Kg.

FIGS. 6A and 6B are set of digital images and a graph illustrating thattreatment with m830 antibody inhibits colon cancer metastasis to liverin an animal model. FIG. 6A shows bioluminescence imaging of athymicnude mice administered intrasplenic injection of human colon cancercells. The bioluminescence signal was quantified (FIG. 6B).

FIG. 7 is a graph illustrating binding of an antibody drug conjugateincluding the fully human m825 antibody conjugated to the MMAE toxin torecombinant TEM8 (AP-TEM8) as well as CHO cells overexpressing TEM8 (CHOTEM8). CHO cells that do not express TEM8 (CHO) were used as a negativecontrol.

FIG. 8 is a graph illustrating that an antibody drug conjugate includingthe fully human m825 antibody conjugated to the MMAE toxin isselectively cytotoxic towards cells expressing TEM8. HEK 293 cells (293)or HEK 293 cells transfected with TEM8 (293/TEM8) were treated with MMAEalone (MMAE), m825 alone (anti-TEM8), or an antibody drug conjugateincluding the fully human m825 antibody conjugated to MMAE(anti-TEM8-MMAE). The MMAE toxin was cytotoxic towards both 293 and293/TEM8 cells, whereas the antibody drug conjugate was selectivelycytotoxic towards 293/TEM8 cells.

FIG. 9 is a graph illustrating regression of human colon cancerxenografts following treatment with an antibody drug conjugate includingthe fully human m825 antibody conjugated to MMAE (m825-MMAE). Coloncancer xenografts (HCT116 cells) were grown subcutaneously in Athymicnude mice. The mice were administered the indicated amount (mg/kg, mpk)of vehicle, m825 antibody alone (M825), or m825-MMAE, twice a week forthree weeks.

FIG. 10 is a graph illustrating regression of human ovarian cancerxenografts following treatment with an antibody drug conjugate includingthe fully human m825 antibody conjugated to MMAE. Ovarian cancerxenografts (OVCAR3 cells) were grown subcutaneously in Athymic nudemice. The mice were administered the indicated amount (mg/kg, mpk) ofvehicle, m825 antibody alone (M825), MMAE alone, or m825-MMAE twice aweek for three and a half weeks.

SEQUENCE LISTING

The nucleic and amino acid sequences listed in the accompanying sequencelisting are shown using standard letter abbreviations for nucleotidebases, and three letter code for amino acids, as defined in 37 C.F.R.1.822. Only one strand of each nucleic acid sequence is shown, but thecomplementary strand is understood as included by any reference to thedisplayed strand. The Sequence Listing is submitted as an ASCII textfile in the form of the file named “Sequence.txt” (˜28 kb), which wascreated on Mar. 14, 2016, which is incorporated by reference herein. Inthe accompanying sequence listing:

SEQ ID NO: 1 is the amino acid sequence of the heavy chain variable region of the m825 mAb.QVQLVQSGAEVKKPGTSVKVSCKVPGYTFSSYAISWVRQAPGQGLEWMGGIIPIFGTTNYAQKFQGRVTITGEESTSTVYMELSSLRSEDTAVYYCARDTDYMFDYWGQGTLVTVSSSEQ ID NO: 2 is the amino acid sequence of the light chain variable region of the m825 mAb.SSELTQDPVVSVALGETVSITCQGDNLRDFYASWYQQKPGQAPLLVMYGKNRRPSGIPDRFSGSTSGNTLSLTITGAQAEDEADYYCSSRDNSKHVVFGGGTKVTVLSEQ ID NO: 3 is the amino acid sequence of the heavy chain variable region of the m822 mAb.QVQLVQSGAEVKKPGASVKVSCKVSGYTFSSYAISWVRQAPGQGLEWMGGIIPIFGTANYAQKFQGRVTITADESTSTAYMELSSLRSEDTAVYYCARDTDYMFDYWGQGTLVTVSSSEQ ID NO: 4 is the amino acid sequence of the light chain variable region of the m822 mAb.SSELTQDPVVSVALGETVSITCQGDNLRDFYASWYQQKPGQAPLLVMYGKNRRPSGIPDRFSGSTSGNTLSLTITGAQAEDEADYYCSSRDNSKHVVFGGGTKVTVLSEQ ID NO: 5 is the amino acid sequence of the heavy chain variable region of the m830 mAb.EVQLVESGGGVVQPGRSVRLSCAASGFTFSTYTMHWVRQAPGKGLEWVAIISNDGSNKYYADPVRGRFTISRDNSKNTLYLQMNSLRAEDTAVYYCVRGSSWYRGNWFDPWGQGTLVTVSSSEQ ID NO: 6 is the amino acid sequence of the light chain variable region of the m830 mAb.DIQMTQSPSSLSASVGDRVTIACRASQTISRYLNWYQQKPGKAPKLLIYAASSLQSGVSSRFSGSGSGTEFTLTISSLQPEDFATYFCQQTYSPPITFGQGTRLEIKRSEQ ID NO: 7 is the amino acid sequence of the heavy chain variable region of the m863 mAb.EVQLVETGAEVKKPGASVKVSCKASGYTFTGYYMHWVRQAPGQGLEWMGWINPTSGSTNYAQKFQGRVTMTRDTSISTAYMELSGLRSDDTAVYYCVRDPGSPKWLAFDPWGQGTLVTVSSSEQ ID NO: 8 is the amino acid sequence of the light chain variable region of the m863 mAb.DIQLTQSPSSLSASVGDRVTITCRASRAISRYLNWYQQKPGKAPKLLIYAASSLQSGVSSRFSGSGSGTEFTLTISSLQPEDFATYFCQQTYSPPITFGQGTRLEIKRSEQ ID NO: 9 is an exemplary cDNA sequence encoding human TEM8  protein (GENBANK ® Accession No. NM_032208.2, incorporated by reference herein  as present in the database on Sep. 10, 2013).SEQ ID NO: 10 is the protein sequence of human TEM8 (GENBANK ®  Accession No. NP_115584.1, incorporated by reference herein as  present in the database on Sep. 10, 2013).SEQ ID NO: 11 is an exemplary cDNA sequence encoding the heavy chain variable region of the m825 mAb.caggtccagctggtgcagtctggggctgaggtgaagaagcctgggacctcagtgaaggtctcctgcaaggttcctggatacaccttcagcagctatgctatcagctgggtgcgacaggcccctggacaagggcttgagtggatgggagggatcatccctatctttggtacaacaaactacgcacagaagttccagggcagagtcacgattaccggggaggaatccacgagcacagtctacatggagctgagcagcctgagatctgaggacacggccgtgtattactgtgcgagagatacggactacatgtttgactactggggccagggaaccctggtcaccgtgagctc aSEQ ID NO: 12 is an exemplary cDNA sequence encoding the light chain variable region of the m825 mAb.tcttctgagctgactcaggaccctgttgtgtctgtggccttgggagagacagtcagtatcacatgccaaggagacaacctcagagacttttatgcaagctggtaccaacagaagccaggacaggcccctctactagtcatgtatggtaaaaacaggcggccctcagggatcccagaccgattctctggctccacctcaggaaacacactttccttgaccatcactggggctcaggcggaagatgaggctgactattactgtagctcccgggacaacagtaagcatgtggtgttcggcggggggaccaaggtcaccgtcctaSEQ ID NO: 13 is an exemplary cDNA sequence encoding the heavy chain variable region of the m822 mAb.caggtccagctggtgcagtctggggctgaggtgaagaagcctggggcctcagtgaaggtctcctgcaaggtttctggatacaccttcagcagctatgctatcagctgggtgcgacaggcccctggacaagggcttgagtggatgggagggatcatccctatctttggtacagcaaactacgcacagaagttccagggcagagtcacgattaccgcggacgaatccacgagcacagcctacatggagctgagcagcctgagatctgaggacacggccgtgtattactgtgcgagagatacggactacatgtttgactactggggccagggaaccctggtcaccgtgagctc aSEQ ID NO: 14 is an exemplary cDNA sequence encoding the light chain variable region of the m822 mAb.tcttctgagctgactcaggaccctgttgtgtctgtggccttgggagagacagtcagtatcacatgccaaggagacaacctcagagacttttatgcaagctggtaccaacagaagccaggacaggcccctctactagtcatgtatggtaaaaacaggcggccctcagggatcccagaccgattctctggctccacctcaggaaacacactttccttgaccatcactggggctcaggcggaagatgaggctgactattactgtagctcccgggacaacagtaagcatgtggtgttcggcggggggaccaaggtcaccgtcctaSEQ ID NO: 15 is an exemplary cDNA sequence encoding the heavy chain variable region of the m830 mAb.gaggtgcagctggtggagtctgggggaggcgtggtccagcctgggaggtccgtgagactctcctgtgcagcctctggattcaccttcagtacctatactatgcactgggtccgccaggctccaggcaaggggctggagtgggtggcaattatctcaaatgatggaagcaataagtactacgcagaccccgtgaggggccgattcaccatctccagagacaattccaagaacacgctgtatctgcaaatgaacagcctgagagctgaggacacggctgtgtattactgtgtacgtggcagcagctggtatcgcggaaattggttcgacccctggggccagggaaccctggtcaccgtgagctcaSEQ ID NO: 16 is an exemplary cDNA sequence encoding the light chain variable region of the m830 mAb.gacatccagatgacccagtctccatcctccctgtctgcatctgtaggagacagagtcaccatcgcttgccgggcaagtcagaccattagtaggtatttaaattggtatcagcagaaaccagggaaagcccctaagctcctgatctatgctgcatccagtttgcaaagtggggtctcatcaaggttcagtggcagtggatctgggacagagttcactctcaccatcagcagtctgcagcctgaagattttgcaacttatttctgtcaacagacttacagtcccccgatcaccttcggccaagggacacgactggagattaaacgaSEQ ID NO: 17 is an exemplary cDNA sequence encoding the heavy chain variable region of the m863 mAb.gaggtgcagctggtggagaccggggctgaggtgaagaagcctggggcctcagtgaaggtctcctgcaaggcttctggatacaccttcaccggctactatatgcactgggtgcgacaggcccctggacaagggcttgagtggatgggatggatcaaccctaccagtggtagcacaaactatgcacagaagtttcagggcagggtcaccatgaccagggacacgtccatcagcacagcctacatggagctgagcgggctgagatctgacgacactgccgtgtattactgtgtgagagatccgggttctcctaagtggctggccttcgacccctggggccagggcaccctggtcaccgtgagctcaSEQ ID NO: 18 is an exemplary cDNA sequence encoding the light chain variable region of the m863 mAb.gacatccagttgacccagtctccatcctccttgtctgcttctgtaggagacagagtcaccatcacttgccgggcaagtcgggccattagtaggtatttaaattggtatcagcagaaaccagggaaagcccctaagctcctgatctatgctgcatccagtttgcaaagtggggtctcatcaaggttcagtggcagtggatctgggacagagttcactctcaccatcagcagtctgcagcctgaagattttgcaacttatttctgtcaacagacttacagtcccccgatcaccttcggccaagggacacgactggagattaaacgt

DETAILED DESCRIPTION I. Summary of Terms

Unless otherwise noted, technical terms are used according toconventional usage. Definitions of common terms in molecular biology canbe found in Benjamin Lewin, Genes VII, published by Oxford UniversityPress, 1999; Kendrew et al. (eds.), The Encyclopedia of MolecularBiology, published by Blackwell Science Ltd., 1994; and Robert A. Meyers(ed.), Molecular Biology and Biotechnology: a Comprehensive DeskReference, published by VCH Publishers, Inc., 1995; and other similarreferences.

As used herein, the singular forms “a,” “an,” and “the,” refer to boththe singular as well as plural, unless the context clearly indicatesotherwise. For example, the term “an antigen” includes single or pluralantigens and can be considered equivalent to the phrase “at least oneantigen.” As used herein, the term “comprises” means “includes.” Thus,“comprising an antigen” means “including an antigen” without excludingother elements. The phrase “and/or” means “and” or “or.” It is furtherto be understood that any and all base sizes or amino acid sizes, andall molecular weight or molecular mass values, given for nucleic acidsor polypeptides are approximate, and are provided for descriptivepurposes, unless otherwise indicated. Although many methods andmaterials similar or equivalent to those described herein can be used,particular suitable methods and materials are described below. In caseof conflict, the present specification, including explanations of terms,will control. In addition, the materials, methods, and examples areillustrative only and not intended to be limiting. To facilitate reviewof the various embodiments, the following explanations of terms areprovided:

Administration: To provide or give to a subject an agent, for example, acomposition that includes a monoclonal antibody that specifically bindsTEM8, such as a conjugate, by any effective route. Exemplary routes ofadministration include, but are not limited to, oral, injection (such assubcutaneous, intramuscular, intradermal, intraperitoneal, andintravenous), sublingual, rectal, transdermal (for example, topical),intranasal, vaginal, and inhalation routes.

Agent: Any substance or any combination of substances that is useful forachieving an end or result; for example, a substance or combination ofsubstances useful for decreasing or reducing pathological angiogenesisin a subject. Agents include effector molecules and detectable markers.In some embodiments, the agent is a detectable marker, chemotherapeuticagent, toxin or anti-angiogenic agent. The skilled artisan willunderstand that particular agents may be useful to achieve more than oneresult; for example, an agent may be useful as both a detectable markerand an anti-angiogenic agent.

Angiogenesis: A biological process leading to the generation of newblood vessels through sprouting or growth from pre-existing bloodvessels. The process involves the migration and proliferation ofendothelial cells from preexisting vessels. Angiogenesis occurs duringpre- and post-natal development, and in the adult. Angiogenesis occursduring the normal cycle of the female reproductive system, woundhealing, and during pathological processes such as cancer, where it isessential for the growth of solid tumors (for review, see Battegay, J.Molec. Med., 73(7): 333-346, 1995; Shchors and Evan, Cancer Res.,67:1630-1633. 2007).

Anthrax: An acute disease caused by the bacterium Bacillus anthracis,and in particular the toxin it produces. Anthrax toxin is a mixture ofthree protein components: (i) protective antigen (PA), (ii) edema factor(EF), and (iii) lethal factor (LF). Cellular entry of Anthrax toxinrequires PA binding to one of its two cell-surface receptors, ANTXR1(aka TEM8) or ANTXR2 (also known as CMG2 receptor), on the host cell(see, for example, Van der Goot and Young, Mol. Aspects Med.,30(6):406-412, 2009; Moayeri and Leppla, Curr Opin Microbiol 7(1):19-24,2004).

Anthrax protective antigen (PA): The protein secreted by Bacillusanthracis that forms the Anthrax toxin with edema factor (EF) and lethalfactor (LF). Cellular entry of Anthrax toxin requires PA binding to oneof its two cell-surface receptors, ANTXR1 (also known as TEM8) or ANTXR2(also known as CMG2 receptor), on the host cell (see, for example, Vander Goot and Young, Mol. Aspects Med., 30(6):406-412, 2009; Moayeri andLeppla, Curr Opin Microbiol 7(1):19-24, 2004). After protease cleavage,PA binds to the two toxic enzymes (EF and LF) and mediates theirtransportation into the cytosol where they exert their pathogeniceffects (Bradley et al., Nature 414:225, 2001). The smaller cleaved 63kD PA remnant (PA₆₃) oligomerizes, exposing a second binding domain andbinds to either EF, an 89 kD protein, to form edema toxin, or LF, a 90kD protein, to form lethal toxin (LeTx) (Leppla et al., Salisbury Med.Bull. Suppl. 68:41-43, 1990), and the complex is internalized into thecell where it enters the endosomal system (Singh et al., Infect. Immun.67:1853, 1999; Friedlander, J. Biol. Chem. 261:7123, 1986). From theseendosomes, the PA₆₃ channel enables translocation of LF and EF to thecytosol by a pH- and voltage-dependent mechanism (Zhao et al., J. Biol.Chem., 270:18626, 1995). In some embodiments, the TEM8 specificantibodies or conjugates including TEM8 specific antibodies disclosedherein are capable of blocking PA binding to TEM8. In one example, PAincludes an amino acid sequence set forth in GENBANK® Accession No.AAF86457, as accessed on Sep. 19, 2013.

Anti-angiogenic agent: A molecule that decreases or reducesangiogenesis, for example, a molecule that decreases pathologicalangiogenesis. In some examples, antibodies that specifically bind TEM8or conjugates including such antibodies are anti-angiogenic agents thatdecrease pathological angiogenesis. Additional anti-angiogenic agentsinclude, but are not limited to, vascular endothelial growth factor(VEGF) antibodies (e.g., bevacizumab) and vascular endothelial growthfactor receptor (VEGFR) antibodies (e.g., such as DC101, produced by theDC101 hybridoma (ATCC No. HB-11534)) or small molecules (such as DMXAA(also known as Vadimezan or 5,6-Dimethyl-9-oxo-9H-xanthen-4-yl)-aceticacid, available from Novartis International AG, Basal, CH, and SigmaCorp., St. Louis, Mo.). (See also, Albini et al., Nat. Rev. Clin.Oncol., 9:498-509, 2012).

Antibody: A polypeptide that specifically binds and recognizes ananalyte (antigen) such as TEM8 protein or an antigenic fragment of TEM8.The term “antibody” is used herein in the broadest sense and encompassesvarious antibody structures, including but not limited to monoclonalantibodies, polyclonal antibodies, multispecific antibodies (e.g.,bispecific antibodies), and antibody fragments, so long as they exhibitthe desired antigen-binding activity.

Non-limiting examples of antibodies include, for example, intactimmunoglobulins and variants and fragments thereof known in the art thatretain binding affinity for the antigen. Examples of antibody fragmentsinclude but are not limited to Fv, Fab, Fab′, Fab′-SH, F(ab′)₂;diabodies; linear antibodies; single-chain antibody molecules (e.g.scFv); and multispecific antibodies formed from antibody fragments.Antibody fragments include antigen binding fragments either produced bythe modification of whole antibodies or those synthesized de novo usingrecombinant DNA methodologies (see, e.g., Kontermann and Dubel (Ed),Antibody Engineering, Vols. 1-2, 2^(nd) Ed., Springer Press, 2010).

A single-chain antibody (scFv) is a genetically engineered moleculecontaining the V_(H) and V_(L) domains of one or more antibody(ies)linked by a suitable polypeptide linker as a genetically fused singlechain molecule (see, for example, Bird et al., Science, 242:423-426,1988; Huston et al., Proc. Natl. Acad. Sci., 85:5879-5883, 1988; Ahmadet al., Clin. Dev. Immunol., 2012, doi:10.1155/2012/980250; Marbry,IDrugs, 13:543-549, 2010). The intramolecular orientation of theV_(H)-domain and the V_(L)-domain in a scFv, is typically not decisivefor scFvs. Thus, scFvs with both possible arrangements(V_(H)-domain-linker domain-V_(L)-domain; V_(L)-domain-linkerdomain-V_(H)-domain) may be used.

In a dsFv the heavy and light chain variable chains have been mutated tointroduce a disulfide bond to stabilize the association of the chains.Diabodies also are included, which are bivalent, bispecific antibodiesin which V_(H) and V_(L) domains are expressed on a single polypeptidechain, but using a linker that is too short to allow for pairing betweenthe two domains on the same chain, thereby forcing the domains to pairwith complementary domains of another chain and creating two antigenbinding sites (see, for example, Holliger et al., Proc. Natl. Acad.Sci., 90:6444-6448, 1993; Poljak et al., Structure, 2:1121-1123, 1994).

Antibodies also include genetically engineered forms such as chimericantibodies (such as humanized murine antibodies) and heteroconjugateantibodies (such as bispecific antibodies). See also, Pierce Catalog andHandbook, 1994-1995 (Pierce Chemical Co., Rockford, Ill.); Kuby, J.,Immunology, 3^(rd) Ed., W.H. Freeman & Co., New York, 1997.

An “antibody that binds to the same epitope” as a reference antibodyrefers to an antibody that blocks binding of the reference antibody toits antigen in a competition assay by 50% or more, and conversely, thereference antibody blocks binding of the antibody to its antigen in acompetition assay by 50% or more. Antibody competition assays are known,and an exemplary competition assay is provided herein.

An antibody may have one or more binding sites. If there is more thanone binding site, the binding sites may be identical to one another ormay be different. For instance, a naturally-occurring immunoglobulin hastwo identical binding sites, a single-chain antibody or Fab fragment hasone binding site, while a bispecific or bifunctional antibody has twodifferent binding sites.

Typically, a naturally occurring immunoglobulin has heavy (H) chains andlight (L) chains interconnected by disulfide bonds. Immunoglobulin genesinclude the kappa, lambda, alpha, gamma, delta, epsilon and mu constantregion genes, as well as the myriad immunoglobulin variable domaingenes. There are two types of light chain, lambda (λ) and kappa (κ).There are five main heavy chain classes (or isotypes) which determinethe functional activity of an antibody molecule: IgM, IgD, IgG, IgA andIgE.

Each heavy and light chain contains a constant region (or constantdomain) and a variable region (or variable domain; see, e.g., Kindt etal. Kuby Immunology, 6.sup.th ed., W.H. Freeman and Co., page 91(2007).) In several embodiments, the heavy and the light chain variableregions combine to specifically bind the antigen. In additionalembodiments, only the heavy chain variable region is required. Forexample, naturally occurring camelid antibodies consisting of a heavychain only are functional and stable in the absence of light chain (see,e.g., Hamers-Casterman et al., Nature, 363:446-448, 1993; Sheriff etal., Nat. Struct. Biol., 3:733-736, 1996). References to “V_(H)” or “VH”refer to the variable region of an antibody heavy chain, including thatof an antigen binding fragment, such as Fv, scFv, dsFv or Fab.References to “V_(L)” or “VL” refer to the variable domain of anantibody light chain, including that of an Fv, scFv, dsFv or Fab.

Light and heavy chain variable regions contain a “framework” regioninterrupted by three hypervariable regions, also called“complementarity-determining regions” or “CDRs” (see, e.g., Kabat etal., Sequences of Proteins of Immunological Interest, U.S. Department ofHealth and Human Services, 1991). The sequences of the framework regionsof different light or heavy chains are relatively conserved within aspecies. The framework region of an antibody, that is the combinedframework regions of the constituent light and heavy chains, serves toposition and align the CDRs in three-dimensional space.

The CDRs are primarily responsible for binding to an epitope of anantigen. The amino acid sequence boundaries of a given CDR can bereadily determined using any of a number of well-known schemes,including those described by Kabat et al. (“Sequences of Proteins ofImmunological Interest,” 5th Ed. Public Health Service, NationalInstitutes of Health, Bethesda, Md., 1991; “Kabat” numbering scheme),Al-Lazikani et al., (JMB 273,927-948, 1997; “Chothia” numbering scheme),and Lefranc et al. (“IMGT unique numbering for immunoglobulin and T cellreceptor variable domains and Ig superfamily V-like domains,” Dev. Comp.Immunol., 27:55-77, 2003; “IMGT” numbering scheme). The CDRs of eachchain are typically referred to as CDR1, CDR2, and CDR3 (from theN-terminus to C-terminus), and are also typically identified by thechain in which the particular CDR is located. Thus, a V_(H) CDR3 is theCDR3 from the variable domain of the heavy chain of the antibody inwhich it is found, whereas a V_(L) CDR1 is the CDR1 from the variabledomain of the light chain of the antibody in which it is found. Lightchain CDRs are sometimes referred to as LCDR1, LCDR2, and LCDR3. Heavychain CDRs are sometimes referred to as LCDR1, LCDR2, and LCDR3.

A “monoclonal antibody” is an antibody produced by a single clone ofB-lymphocytes or by a cell into which nucleic acid encoding the lightand heavy variable regions of the antibody of a single antibody (or anantigen binding fragment thereof) have been transfected, or a progenythereof. Monoclonal antibodies are produced by methods known to those ofskill in the art, for instance by making hybrid antibody-forming cellsfrom a fusion of myeloma cells with immune spleen cells. These fusedcells and their progeny are termed “hybridomas.” In some examplesmonoclonal antibodies are isolated from a subject. Monoclonal antibodiescan have conservative amino acid substitutions which have substantiallyno effect on antigen binding or other immunoglobulin functions. (See,for example, Harlow & Lane, Antibodies, A Laboratory Manual, 2^(nd) ed.Cold Spring Harbor Publications, New York (2013).)

A “humanized” antibody or antigen binding fragment includes a humanframework region and one or more CDRs from a non-human (such as a mouse,rat, or synthetic) antibody or antigen binding fragment. The non-humanantibody or antigen binding fragment providing the CDRs is termed a“donor,” and the human antibody or antigen binding fragment providingthe framework is termed an “acceptor.” In one embodiment, all the CDRsare from the donor immunoglobulin in a humanized immunoglobulin.Constant regions need not be present, but if they are, they can besubstantially identical to human immunoglobulin constant regions, suchas at least about 85-90%, such as about 95% or more identical. Hence,all parts of a humanized antibody or antigen binding fragment, exceptpossibly the CDRs, are substantially identical to corresponding parts ofnatural human antibody sequences.

A “chimeric antibody” is an antibody which includes sequences derivedfrom two different antibodies, which typically are of different species.In some examples, a chimeric antibody includes one or more CDRs and/orframework regions from one human antibody and CDRs and/or frameworkregions from another human antibody.

A “fully human antibody” or “human antibody” is an antibody whichincludes that are based on sequences from (or derived from) the humangenome, and does not include sequence from another species. In someembodiments, a human antibody includes CDRs, framework regions, and (ifpresent) an Fc region from (or derived from) the human genome. Humanantibodies can be identified and isolated using technologies forcreating antibodies based on sequences derived from the human genome,for example by phage display or using transgenic animals (see, e.g.,Barbas et al. Phage display: A Laboratory Manuel. 1^(st) Ed. New York:Cold Spring Harbor Laboratory Press, 2004. Print.; Lonberg, Nat.Biotech., 23: 1117-1125, 2005; Lonenberg, Curr. Opin. Immunol.,20:450-459, 2008)

Binding affinity: Affinity of an antibody or antigen binding fragmentthereof for an antigen. In one embodiment, affinity is calculated by amodification of the Scatchard method described by Frankel et al., Mol.Immunol., 16:101-106, 1979. In another embodiment, binding affinity ismeasured by an antigen/antibody dissociation rate. In yet anotherembodiment, a high binding affinity is measured by a competitionradioimmunoassay. In several examples, a high binding affinity is atleast about 1×10⁻⁸ M. In other embodiments, a high binding affinity isat least about 1.0×10⁻⁹, at least about 5.0×10⁻⁹, at least about1.0×10⁻¹⁰, at least about 5.0×10⁻¹⁰, or at least about 1.0×10⁻¹¹.

Biological sample: A sample obtained from a subject. Biological samplesinclude all clinical samples useful for detection of disease orinfection (for example, cancer or Anthrax infection) in subjects,including, but not limited to, cells, tissues, and bodily fluids, suchas blood, derivatives and fractions of blood (such as serum),cerebrospinal fluid; as well as biopsied or surgically removed tissue,for example tissues that are unfixed, frozen, or fixed in formalin orparaffin. In a particular example, a biological sample is obtained froma subject having or suspected of having a tumor; for example, a subjecthaving or suspected of having breast, colorectal, lung, or skin cancer.In some examples, the subject has or is suspected of having a carcinoma.

Bispecific antibody: A recombinant molecule composed of two differentantigen binding domains that consequently bind to two differentantigenic epitopes. Bispecific antibodies include chemically orgenetically linked molecules of two antigen-binding domains. The antigenbinding domains can be linked using a linker. The antigen bindingdomains can be monoclonal antibodies, antigen-binding fragments (e.g.,Fab, scFv), eAds, bispecific single chain antibodies or combinationsthereof. A bispecific antibody can include one or more constant domains,but does not necessarily include a constant domain. An example of abispecific antibody is a bispecific single chain antibody including ascFv that specifically binds to TEM8 joined (via a peptide linker) to ascFv that specifically binds to an antigen other than TEM8. Anotherexample is a bispecific antibody including a Fab that specifically bindsto TEM8 joined to a scFv that specifically binds to an antigen otherthan TEM8.

Breast cancer: A neoplastic tumor of breast tissue that is or haspotential to be malignant. The most common type of breast cancer isbreast carcinoma, such as ductal carcinoma. Ductal carcinoma in situ isa non-invasive neoplastic condition of the ducts. Lobular carcinoma isnot an invasive disease but is an indicator that a carcinoma maydevelop. Infiltrating (malignant) carcinoma of the breast can be dividedinto stages (I, IIA, IIB, IIIA, IIIB, and IV). See, for example,Bonadonna et al., (eds), Textbook of Breast Cancer: A clinical Guide theTherapy. 3^(rd); London, Tayloy & Francis, 2006.

Carcinoma: A malignant tumor including transformed epithelial cells.Non-limiting examples of carcinomas include adenocarcinoma, squamouscell carcinoma, anaplastic carcinoma and large and small cell carcinoma.In some examples, a carcinoma is a breast carcinoma, colorectalcarcinoma, lung carcinoma or melanoma.

Chemotherapeutic agent: Any chemical agent with therapeutic usefulnessin the treatment of diseases characterized by abnormal cell growth. Forexample, chemotherapeutic agents are useful for the treatment of cancer,including breast, colorectal, lung, and skin cancer. In one embodiment,a chemotherapeutic agent is an agent of use in treating a carcinoma.Particular examples of additional therapeutic agents that can be usedinclude microtubule binding agents, DNA intercalators or cross-linkers,DNA synthesis inhibitors, DNA and RNA transcription inhibitors,antibodies, enzymes, enzyme inhibitors, gene regulators, andangiogenesis inhibitors. In one embodiment, a chemotherapeutic agent isa radioactive compound. Other examples include the anti-neoplastic drugs5-fluorouracil (5-FU) and IRT. In particular examples, suchchemotherapeutic agents are administered in combination with a treatmentthat decreases or reduces angiogenesis (for example before, during, orafter administration of a therapeutically effective amount of one ormore antibodies that specifically bind to TEM8 or a conjugate thereof).One of skill in the art can readily identify a chemotherapeutic agent ofuse (see for example, Slapak and Kufe, Principles of Cancer Therapy,Chapter 86 in Harrison's Principles of Internal Medicine, 14th edition;Perry et al., Chemotherapy, Ch. 17 in Abeloff, Clinical Oncology 2^(nd)ed., © 2000 Churchill Livingstone, Inc; Baltzer, L., Berkery, R. (eds):Oncology Pocket Guide to Chemotherapy, 2^(nd) ed. St. Louis, Mosby-YearBook, 1995; Fischer, D. S., Knobf, M. F., Durivage, H J. (eds): TheCancer Chemotherapy Handbook, 4th ed. St. Louis, Mosby-Year Book, 1993;Chabner and Longo, Cancer Chemotherapy and Biotherapy: Principles andPractice (4th ed.). Philadelphia: Lippincott Willians & Wilkins, 2005;Skeel, Handbook of Cancer Chemotherapy (6th ed.). Lippincott Williams &Wilkins, 2003). Combination chemotherapy is the administration of morethan one agent to treat cancer.

Chimeric antibody: An antibody which includes sequences derived from twodifferent antibodies, such as from different species. In some examples,a chimeric antibody includes one or more CDRs and/or framework regionsfrom one human antibody and CDRs and/or framework regions from anotherhuman antibody.

Chimeric Antigen Receptor (CAR): An engineered T cell receptor having anextracellular antibody-derived targeting domain (such as an scFv) joinedto one or more intracellular signaling domains of a T cell receptor. A“chimeric antigen receptor T cell” is a T cell expressing a CAR, and hasantigen specificity determined by the antibody-derived targeting domainof the CAR. Methods of making CARs (e.g., for treatment of cancer) areavailable (see, e.g., Park et al., Trends Biotechnol., 29:550-557, 2011;Grupp et al., N Engl J Med., 368:1509-1518, 2013; Han et al., J. HematolOncol., 6:47, 2013; PCT Pubs. WO2012/079000, WO2013/059593; and U.S.Pub. 2012/0213783, each of which is incorporated by reference herein inits entirety.)

Colorectal cancer: A neoplastic tumor of colon, rectum or anus tissuethat is or has the potential to be malignant. The main types ofcolorectal cancer include colorectal carcinomas such as adenocarcinomaand squamous cell carcinoma. Infiltrating (malignant) carcinoma of thecolon can be divided into stages (I, II, III and IV). See, for example,Blake et al. (eds.), Gastrointestinal Oncology: A practical Guide,Berlin: Springer-Verlag, 2011.

Conditions sufficient to form an immune complex: Conditions which allowan antibody or antigen binding fragment thereof to bind to its cognateepitope to a detectably greater degree than, and/or to the substantialexclusion of, binding to substantially all other epitopes. Conditionssufficient to form an immune complex are dependent upon the format ofthe binding reaction and typically are those utilized in immunoassayprotocols or those conditions encountered in vivo. See Harlow & Lane,infra, for a description of immunoassay formats and conditions. Theconditions employed in the methods are “physiological conditions” whichinclude reference to conditions (e.g., temperature, osmolarity, pH) thatare typical inside a living mammal or a mammalian cell. While it isrecognized that some organs are subject to extreme conditions, theintra-organismal and intracellular environment normally lies around pH 7(e.g., from pH 6.0 to pH 8.0, more typically pH 6.5 to 7.5), containswater as the predominant solvent, and exists at a temperature above 0°C. and below 50° C. Osmolarity is within the range that is supportive ofcell viability and proliferation.

Conjugate: A complex of two molecules linked together, for example,linked together by a covalent bond. In one embodiment, an antibody islinked to an effector molecule; for example, an antibody thatspecifically binds to TEM8 covalently linked to an effector molecule.The linkage can be by chemical or recombinant means. In one embodiment,the linkage is chemical, wherein a reaction between the antibody moietyand the effector molecule has produced a covalent bond formed betweenthe two molecules to form one molecule. A peptide linker (short peptidesequence) can optionally be included between the antibody and theeffector molecule. Because conjugates can be prepared from two moleculeswith separate functionalities, such as an antibody and an effectormolecule, they are also sometimes referred to as “chimeric molecules.”

Conservative variant: “Conservative” amino acid substitutions are thosesubstitutions that do not substantially decrease the binding affinity ofan antibody for an antigen (for example, the binding affinity of anantibody for TEM8). For example, a human antibody that specificallybinds TEM8 can include at most about 1, at most about 2, at most about5, at most about 10, or at most about 15 conservative substitutions andspecifically bind the TEM8 polypeptide. The term conservative variationalso includes the use of a substituted amino acid in place of anunsubstituted parent amino acid, provided that antibody retains bindingaffinity for TEM8. Non-conservative substitutions are those that reducean activity or binding to TEM8.

Conservative amino acid substitution tables providing functionallysimilar amino acids are well known to one of ordinary skill in the art.The following six groups are examples of amino acids that are consideredto be conservative substitutions for one another:

1) Alanine (A), Serine (S), Threonine (T);

2) Aspartic acid (D), Glutamic acid (E);

3) Asparagine (N), Glutamine (Q);

4) Arginine (R), Lysine (K);

5) Isoleucine (I), Leucine (L), Methionine (M), Valine (V); and

6) Phenylalanine (F), Tyrosine (Y), Tryptophan (W).

Contacting: Placement in direct physical association; includes both insolid and liquid form, which can take place either in vivo or in vitro.Contacting includes contact between one molecule and another molecule,for example the amino acid on the surface of one polypeptide, such as anantigen, that contacts another polypeptide, such as an antibody.Contacting can also include contacting a cell for example by placing anantibody in direct physical association with a cell.

Control: A reference standard. In some embodiments, the control is anegative control, such as tissue sample obtained from a patient thatdoes not have cancer, or a tissue sample from a tissue that isnon-cancerous. In other embodiments, the control is a positive control,such as a tissue sample obtained from a patient diagnosed with cancer,or a tissue sample from a cancerous tissue. In still other embodiments,the control is a historical control or standard reference value or rangeof values (such as a previously tested control sample, such as a groupof cancer patients with known prognosis or outcome, or group of samplesthat represent baseline or normal values).

A difference between a test sample and a control can be an increase orconversely a decrease. The difference can be a qualitative difference ora quantitative difference, for example a statistically significantdifference. In some examples, a difference is an increase or decrease,relative to a control, of at least about 5%, such as at least about 10%,at least about 20%, at least about 30%, at least about 40%, at leastabout 50%, at least about 60%, at least about 70%, at least about 80%,at least about 90%, at least about 100%, at least about 150%, at leastabout 200%, at least about 250%, at least about 300%, at least about350%, at least about 400%, or at least about 500%.

Decrease or Reduce: To reduce the quality, amount, or strength ofsomething; for example a reduction in tumor burden. In one example, atherapy reduces a tumor (such as the size of a tumor, the number oftumors, the metastasis of a tumor, or combinations thereof), or one ormore symptoms associated with a tumor (such as pathological angiogenesisof the tumor or tumors), for example as compared to the response in theabsence of the therapy. In a particular example, a therapy decreases thesize of a tumor, the number of tumors, the metastasis of a tumor, orcombinations thereof, subsequent to the therapy, such as a decrease ofat least 10%, at least 20%, at least 30%, at least 40%, at least 50%, atleast 60%, at least 70%, at least 80%, or at least 90%. Such decreasescan be measured using the methods disclosed herein.

Degenerate variant: In the context of the present disclosure, a“degenerate variant” refers to a polynucleotide encoding a protein (forexample, an antibody that specifically binds TEM8) that includes asequence that is degenerate as a result of the genetic code. There aretwenty natural amino acids, most of which are specified by more than onecodon. Therefore, all degenerate nucleotide sequences are included aslong as the amino acid sequence of the antibody that binds TEM8 encodedby the nucleotide sequence is unchanged.

Detectable marker: A detectable molecule (also known as a label) that isconjugated directly or indirectly to a second molecule, such as anantibody, to facilitate detection of the second molecule. For example,the detectable marker can be capable of detection by ELISA,spectrophotometry, flow cytometry, microscopy or diagnostic imagingtechniques (such as CT scans, MRIs, ultrasound, fiberoptic examination,and laparoscopic examination). Specific, non-limiting examples ofdetectable markers include fluorophores, chemiluminescent agents,enzymatic linkages, radioactive isotopes and heavy metals or compounds(for example super paramagnetic iron oxide nanocrystals for detection byMRI). In one example, a “labeled antibody” refers to incorporation ofanother molecule in the antibody. For example, the label is a detectablemarker, such as the incorporation of a radiolabeled amino acid orattachment to a polypeptide of biotinyl moieties that can be detected bymarked avidin (for example, streptavidin containing a fluorescent markeror enzymatic activity that can be detected by optical or colorimetricmethods). Various methods of labeling polypeptides and glycoproteins areknown in the art and may be used. Examples of labels for polypeptidesinclude, but are not limited to, the following: radioisotopes orradionuclides (such as ³⁵S or ¹³¹I), fluorescent labels (such asfluorescein isothiocyanate (FITC), rhodamine, lanthanide phosphors),enzymatic labels (such as horseradish peroxidase, beta-galactosidase,luciferase, alkaline phosphatase), chemiluminescent markers, biotinylgroups, predetermined polypeptide epitopes recognized by a secondaryreporter (such as a leucine zipper pair sequences, binding sites forsecondary antibodies, metal binding domains, epitope tags), or magneticagents, such as gadolinium chelates. In some embodiments, labels areattached by spacer arms of various lengths to reduce potential sterichindrance. Methods for using detectable markers and guidance in thechoice of detectable markers appropriate for various purposes arediscussed for example in Sambrook et al. (Molecular Cloning: ALaboratory Manual, Cold Spring Harbor, N.Y., 2012) and Ausubel et al.(In Current Protocols in Molecular Biology, John Wiley & Sons, New York,through supplement 104, 2013).

Detecting: To identify the existence, presence, or fact of something.General methods of detecting are known to the skilled artisan and may besupplemented with the protocols and reagents disclosed herein. Forexample, included herein are methods of detecting an endothelial cellthat expresses TEM8 in a subject. In some examples, detecting anendothelial cell that expresses TEM8 detects pathological angiogenesisin the subject.

Effective amount: The amount of an agent (such as a TEM8 specificantibody or a conjugate including a TEM8 specific antibody) that alone,or together with one or more additional agents, induces the desiredresponse, such as, for example formation of a detectable immune complexwith TEM8.

Effector molecule: A molecule intended to have or produce a desiredeffect; for example, a desired effect on a cell to which the effectormolecule is targeted. Effector molecules include such molecules aspolypeptides, radioisotopes and small molecules. Non-limiting examplesof effector molecules include toxins, chemotherapeutic agents andanti-angiogenic agents. The skilled artisan will understand that someeffector molecules may have or produce more than one desired effect. Inone example, an effector molecule is the portion of a chimeric molecule,for example a chimeric molecule that includes a disclosed antibody orfragment thereof, that is intended to have a desired effect on a cell towhich the chimeric molecule is targeted.

Endothelial cell: A cell from the endothelium, which is the thin layerof cells that line the interior surface of blood vessels.

Epitope: An antigenic determinant. These are particular chemical groupsor peptide sequences on a molecule that are antigenic, i.e. that elicita specific immune response. An antibody specifically binds a particularantigenic epitope on a polypeptide. In some examples a disclosedantibody specifically binds to an epitope on TEM8.

Expressed: Translation of a nucleic acid into a protein. Proteins may beexpressed and remain intracellular, become a component of the cellsurface membrane, or be secreted into the extracellular matrix ormedium.

Expression Control Sequences: Nucleic acid sequences that regulate theexpression of a heterologous nucleic acid sequence to which it isoperatively linked. Expression control sequences are operatively linkedto a nucleic acid sequence when the expression control sequences controland regulate the transcription and, as appropriate, translation of thenucleic acid sequence. Thus expression control sequences can includeappropriate promoters, enhancers, transcription terminators, a startcodon (i.e., ATG) in front of a protein-encoding gene, splicing signalfor introns, maintenance of the correct reading frame of that gene topermit proper translation of mRNA, and stop codons. The term “controlsequences” is intended to include, at a minimum, components whosepresence can influence expression, and can also include additionalcomponents whose presence is advantageous, for example, leader sequencesand fusion partner sequences. Expression control sequences can include apromoter.

A promoter is a minimal sequence sufficient to direct transcription.Also included are those promoter elements which are sufficient to renderpromoter-dependent gene expression controllable for cell-type specific,tissue-specific, or inducible by external signals or agents; suchelements may be located in the 5′ or 3′ regions of the gene. Bothconstitutive and inducible promoters are included (see for example,Bitter et al., Methods in Enzymology 153:516-544, 1987). For example,when cloning in bacterial systems, inducible promoters such as pL ofbacteriophage lambda, plac, ptrp, ptac (ptrp-lac hybrid promoter) andthe like may be used. In one embodiment, when cloning in mammalian cellsystems, promoters derived from the genome of mammalian cells (such asmetallothionein promoter) or from mammalian viruses (such as theretrovirus long terminal repeat; the adenovirus late promoter; thevaccinia virus 7.5K promoter) can be used. Promoters produced byrecombinant DNA or synthetic techniques may also be used to provide fortranscription of the nucleic acid sequences. A polynucleotide can beinserted into an expression vector that contains a promoter sequencewhich facilitates the efficient transcription of the inserted geneticsequence of the host. The expression vector typically contains an originof replication, a promoter, as well as specific nucleic acid sequencesthat allow phenotypic selection of the transformed cells.

Expression vector: A vector comprising a recombinant polynucleotidecomprising expression control sequences operatively linked to anucleotide sequence to be expressed. An expression vector comprisessufficient cis-acting elements for expression; other elements forexpression can be supplied by the host cell or in an in vitro expressionsystem. Expression vectors include all those known in the art, such ascosmids, plasmids (e.g., naked or contained in liposomes) and viruses(e.g., lentiviruses, retroviruses, adenoviruses, and adeno-associatedviruses) that incorporate the recombinant polynucleotide.

Framework Region: Amino acid sequences interposed between CDRs in aheavy or light variable region of an antibody. Includes variable lightand variable heavy framework regions. The framework regions serve tohold the CDRs in an appropriate orientation.

IgA: A polypeptide belonging to the class of antibodies that aresubstantially encoded by a recognized immunoglobulin alpha gene. Inhumans, this class or isotype includes IgA₁ and IgA₂. IgA antibodies canexist as monomers, polymers (referred to as pIgA) of predominantlydimeric form, and secretory IgA. The constant chain of wild-type IgAcontains an 18-amino-acid extension at its C-terminus called the tailpiece (tp). Polymeric IgA is secreted by plasma cells with a 15-kDapeptide called the J chain linking two monomers of IgA through theconserved cysteine residue in the tail piece.

IgG: A polypeptide belonging to the class or isotype of antibodies thatare substantially encoded by a recognized immunoglobulin gamma gene. Inhumans, this class includes IgG₁, IgG₂, IgG₃, and IgG. In mice, thisclass includes IgG₁, IgG_(2a), IgG_(2b), and IgG₃.

Immune complex: The binding of antibody or antigen binding fragment(such as a scFv) to a soluble antigen forms an immune complex. Theformation of an immune complex can be detected through conventionalmethods known to the skilled artisan, for instance immunohistochemistry,immunoprecipitation, flow cytometry, immunofluorescence microscopy,ELISA, immunoblotting (for example, Western blot), magnetic resonanceimaging, CT scans, X-ray and affinity chromatography. Immunologicalbinding properties of selected antibodies may be quantified usingmethods well known in the art.

Inhibiting or Treating a Disease: A therapeutic intervention (forexample, administration of a therapeutically effective amount of anantibody that specifically binds TEM8 or a conjugate thereof) thatreduces a sign or symptom of a disease or pathological condition relatedto a disease (such as a tumor or Anthrax infection). Treatment can alsoinduce remission or cure of a condition, such as a tumor or Anthraxinfection. In particular examples, treatment includes preventing atumor, for example by inhibiting the full development of a tumor, suchas preventing development of a metastasis or the development of aprimary tumor. Prevention does not require a total absence of a tumor.

Reducing a sign or symptom of a disease or pathological conditionrelated to a disease, refers to any observable beneficial effect of thetreatment. Reducing a sign or symptom associated with a tumor (such aspathological angiogenesis) can be evidenced, for example, by a delayedonset of clinical symptoms of the disease in a susceptible subject (suchas a subject having a tumor which has not yet metastasized), a reductionin severity of some or all clinical symptoms of the disease, a slowerprogression of the disease (for example by prolonging the life of asubject having tumor), a reduction in the number of relapses of thedisease, an improvement in the overall health or well-being of thesubject, or by other parameters well known in the art that are specificto the particular tumor. A “prophylactic” treatment is a treatmentadministered to a subject who does not exhibit signs of a disease orexhibits only early signs for the purpose of decreasing the risk ofdeveloping pathology.

Isolated: A biological component (such as a nucleic acid, peptide,protein or protein complex, for example an antibody) that has beensubstantially separated, produced apart from, or purified away fromother biological components in the cell of the organism in which thecomponent naturally occurs, that is, other chromosomal andextra-chromosomal DNA and RNA, and proteins. Thus, isolated nucleicacids, peptides and proteins include nucleic acids and proteins purifiedby standard purification methods. The term also embraces nucleic acids,peptides and proteins prepared by recombinant expression in a host cell,as well as, chemically synthesized nucleic acids. A isolated nucleicacid, peptide or protein, for example an antibody, can be at least 50%,at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, atleast 96%, at least 97%, at least 98%, or at least 99% pure.

K_(d): The dissociation constant for a given interaction, such as apolypeptide ligand interaction or an antibody antigen interaction. Forexample, for the bimolecular interaction of an antibody or antigenbinding fragment (such as 35022 or an antigen binding fragment thereof)and an antigen (such as TWM8 protein) it is the concentration of theindividual components of the bimolecular interaction divided by theconcentration of the complex.

Linker: A bi-functional molecule that can be used to link two moleculesinto one contiguous molecule, for example, to link an effector moleculeto an antibody. In some embodiments, the provided conjugates include alinker between the effector molecule or detectable marker and anantibody. In some embodiments, the linker is selectively cleavable, forexample, cleavable under intracellular conditions, such that cleavage ofthe linker releases the effector molecule or detectable marker from theantibody in the intracellular environment. Selectively cleavable refersto cleaving in response to a preselected condition or stimulus. In yetother embodiments, the linker is not cleavable and the effector moleculeor detectable marker can be released, for example, by antibodydegradation. In some cases, a linker is a peptide within an antigenbinding fragment (such as an Fv fragment) which serves to indirectlybond the variable heavy chain to the variable light chain.

The terms “conjugating,” “joining,” “bonding,” or “linking” can refer tomaking two molecules into one contiguous molecule; for example, linkingtwo polypeptides into one contiguous polypeptide, or covalentlyattaching an effector molecule or detectable marker radionuclide orother molecule to a polypeptide, such as an scFv. In the specificcontext, the terms include reference to joining a ligand, such as anantibody moiety, to an effector molecule. The linkage can be either bychemical or recombinant means. “Chemical means” refers to a reactionbetween the antibody moiety and the effector molecule such that there isa covalent bond formed between the two molecules to form one molecule.

Lung cancer: A neoplastic tumor of lung tissue that is or has thepotential to be malignant. The main types of lung cancer are lungcarcinomas: adenocarcinoma, small cell carcinoma, squamous cellcarcinoma, or non-small cell carcinoma. Lung cancer is typically stagedfrom I to IV; other classifications are also used, for examplesmall-cell lung carcinoma can be classified as limited stage if it isconfined to one half of the chest and within the scope of a singleradiotherapy field; otherwise, it is extensive stage. See, for example,Hansen (ed.), Textbook of Lung Cancer, 2^(nd), London: InformaHealthcare, 2008.

Neutralizing antibody: An antibody that is able to specifically bind toa target protein in such a way as to inhibit a biological functionassociated with that target protein. In general, any protein that canperform this type of specific blocking activity is considered aneutralizing protein; neutralizing antibodies are therefore a specificclass of neutralizing protein.

Neoplasia, cancer, or tumor: A neoplasm is an abnormal growth of tissueor cells that results from excessive cell division. Neoplastic growthcan produce a tumor. The amount of a tumor in an individual is the“tumor burden” which can be measured as the number, volume, or weight ofthe tumor. A tumor that does not metastasize is referred to as “benign.”A tumor that invades the surrounding tissue or can metastasize (or both)is referred to as “malignant.”

Tumors of the same tissue type are primary tumors originating in aparticular organ (such as colon, skin, breast, prostate, bladder orlung). Tumors of the same tissue type may be divided into tumors ofdifferent sub-types. For examples, lung carcinomas can be divided intoan adenocarcinoma, small cell, squamous cell, or non-small cell tumors.

Examples of solid tumors, such as sarcomas (connective tissue cancer)and carcinomas (epithelial cell cancer), include fibrosarcoma,myxosarcoma, liposarcoma, chondrosarcoma, osteogenic sarcoma, and othersarcomas, synovioma, mesothelioma, Ewing's tumor, leiomyosarcoma,rhabdomyosarcoma, colorectal carcinoma, lymphoid malignancy, pancreaticcancer, breast cancer, lung cancers, ovarian cancer, prostate cancer,hepatocellular carcinoma, squamous cell carcinoma, basal cell carcinoma,adenocarcinoma, sweat gland carcinoma, medullary thyroid carcinoma,papillary thyroid carcinoma, pheochromocytomas sebaceous glandcarcinoma, papillary carcinoma, papillary adenocarcinomas, medullarycarcinoma, bronchogenic carcinoma, renal cell carcinoma, hepatoma, bileduct carcinoma, choriocarcinoma, Wilms' tumor, cervical cancer,testicular tumor, seminoma, bladder carcinoma, and CNS tumors (such as aglioma, astrocytoma, medulloblastoma, craniopharyogioma, ependymoma,pinealoma, hemangioblastoma, acoustic neuroma, oligodendroglioma,menangioma, melanoma, neuroblastoma and retinoblastoma).

Nucleic acid: A polymer composed of nucleotide units (ribonucleotides,deoxyribonucleotides, related naturally occurring structural variants,and synthetic non-naturally occurring analogs thereof) linked viaphosphodiester bonds, related naturally occurring structural variants,and synthetic non-naturally occurring analogs thereof. Thus, the termincludes nucleotide polymers in which the nucleotides and the linkagesbetween them include non-naturally occurring synthetic analogs, such as,for example and without limitation, phosphorothioates, phosphoramidates,methyl phosphonates, chiral-methyl phosphonates, 2-O-methylribonucleotides, peptide-nucleic acids (PNAs), and the like. Suchpolynucleotides can be synthesized, for example, using an automated DNAsynthesizer. The term “oligonucleotide” typically refers to shortpolynucleotides, generally no greater than about 50 nucleotides. It willbe understood that when a nucleotide sequence is represented by a DNAsequence (i.e., A, T, G, C), this also includes an RNA sequence (i.e.,A, U, G, C) in which “U” replaces “T.”

Conventional notation is used herein to describe nucleotide sequences:the left-hand end of a single-stranded nucleotide sequence is the5′-end; the left-hand direction of a double-stranded nucleotide sequenceis referred to as the 5′-direction. The direction of 5′ to 3′ additionof nucleotides to nascent RNA transcripts is referred to as thetranscription direction. The DNA strand having the same sequence as anmRNA is referred to as the “coding strand;” sequences on the DNA strandhaving the same sequence as an mRNA transcribed from that DNA and whichare located 5′ to the 5′-end of the RNA transcript are referred to as“upstream sequences;” sequences on the DNA strand having the samesequence as the RNA and which are 3′ to the 3′ end of the coding RNAtranscript are referred to as “downstream sequences.”

“cDNA” refers to a DNA that is complementary or identical to an mRNA, ineither single stranded or double stranded form.

“Encoding” refers to the inherent property of specific sequences ofnucleotides in a polynucleotide, such as a gene, a cDNA, or an mRNA, toserve as templates for synthesis of other polymers and macromolecules inbiological processes having either a defined sequence of nucleotides(i.e., rRNA, tRNA and mRNA) or a defined sequence of amino acids and thebiological properties resulting therefrom. Thus, a gene encodes aprotein if transcription and translation of mRNA produced by that geneproduces the protein in a cell or other biological system. Both thecoding strand, the nucleotide sequence of which is identical to the mRNAsequence and is usually provided in sequence listings, and non-codingstrand, used as the template for transcription, of a gene or cDNA can bereferred to as encoding the protein or other product of that gene orcDNA. Unless otherwise specified, a “nucleotide sequence encoding anamino acid sequence” includes all nucleotide sequences that aredegenerate versions of each other and that encode the same amino acidsequence. Nucleotide sequences that encode proteins and RNA may includeintrons.

A polynucleotide or nucleic acid sequence refers to a polymeric form ofnucleotide at least 10 bases in length. A recombinant polynucleotideincludes a polynucleotide that is not immediately contiguous with bothof the coding sequences with which it is immediately contiguous (one onthe 5′ end and one on the 3′ end) in the naturally occurring genome ofthe organism from which it is derived. The term therefore includes, forexample, a recombinant DNA which is incorporated into a vector; into anautonomously replicating plasmid or virus; or into the genomic DNA of aprokaryote or eukaryote, or which exists as a separate molecule (e.g., acDNA) independent of other sequences. The nucleotides can beribonucleotides, deoxyribonucleotides, or modified forms of eithernucleotide. The term includes single- and double-stranded forms of DNA.

Operably linked: A first nucleic acid sequence is operably linked with asecond nucleic acid sequence when the first nucleic acid sequence isplaced in a functional relationship with the second nucleic acidsequence. For instance, a promoter, such as the CMV promoter, isoperably linked to a coding sequence if the promoter affects thetranscription or expression of the coding sequence. Generally, operablylinked DNA sequences are contiguous and, where necessary to join twoprotein-coding regions, in the same reading frame.

Pathological angiogenesis: Angiogenesis that is medically undesired orharmful to a subject, such as angiogenesis associated with a tumor orthe generation of blood vessels in or surrounding a tumor. Tumorvasculature can be distinct from normal vasculature in that severalgenes can be differentially expressed in tumor-associated blood vessels(St. Croix et al., Science, 289, 1197-1202, 2000). One of these genes,tumor endothelial marker 8 (TEM 8), is upregulated in the vasculature ofmalignant solid tumors, with limited expression in healthy tissues.Other examples of pathological angiogenesis include corneal or retinalangiogenesis (as in a corneal transplant or the retina of a subject withmacular degeneration or diabetes).

Pharmaceutically acceptable carriers: The pharmaceutically acceptablecarriers of use are conventional. Remington's Pharmaceutical Sciences,by E. W. Martin, Mack Publishing Co., Easton, Pa., 19th Edition, 1995,describes compositions and formulations suitable for pharmaceuticaldelivery of the disclosed antibodies.

In general, the nature of the carrier will depend on the particular modeof administration being employed. For instance, parenteral formulationsusually comprise injectable fluids that include pharmaceutically andphysiologically acceptable fluids such as water, physiological saline,balanced salt solutions, aqueous dextrose, glycerol or the like as avehicle. For solid compositions (e.g., powder, pill, tablet, or capsuleforms), conventional non-toxic solid carriers can include, for example,pharmaceutical grades of mannitol, lactose, starch, or magnesiumstearate. In addition to biologically neutral carriers, pharmaceuticalcompositions to be administered can contain minor amounts of non-toxicauxiliary substances, such as wetting or emulsifying agents,preservatives, and pH buffering agents and the like, for example sodiumacetate or sorbitan monolaurate. In particular embodiments, suitable foradministration to a subject the carrier may be sterile, and/or suspendedin a unit dosage form containing one or more measured doses of thecomposition suitable to induce the desired response. It may also beaccompanied by medications for its use for treatment purposes. The unitdosage form may be, for example, in a sealed vial that contains sterilecontents or a syringe for injection into a subject.

Polypeptide: A polymer in which the monomers are amino acid residuesthat are joined together through amide bonds. When the amino acids arealpha-amino acids, either the L-optical isomer or the D-optical isomercan be used, the L-isomers being preferred. The terms “polypeptide” or“protein” as used herein are intended to encompass any amino acidsequence and include modified sequences such as glycoproteins. Apolypeptide includes both naturally occurring proteins, as well as thosethat are recombinantly or synthetically produced. A polypeptide has anamino terminal (N-terminal) end and a carboxy-terminal end. In someembodiments, the polypeptide is a disclosed antibody or a fragmentthereof.

Polypeptide modifications: Polypeptides can be modified by a variety ofchemical techniques to produce derivatives having essentially the sameactivity and conformation as the unmodified peptides, and optionallyhaving other desirable properties. For example, carboxylic acid groupsof the protein, whether carboxyl-terminal or side chain, may be providedin the form of a salt of a pharmaceutically-acceptable cation oresterified to form a C₁-C₁₆ ester, or converted to an amide of formulaNR₁R₂ wherein R₁ and R₂ are each independently H or C₁-C₁₆ alkyl, orcombined to form a heterocyclic ring, such as a 5- or 6-membered ring.Amino groups of the peptide, whether amino-terminal or side chain, maybe in the form of a pharmaceutically-acceptable acid addition salt, suchas the HCl, HBr, acetic, benzoic, toluene sulfonic, maleic, tartaric andother organic salts, or may be modified to C₁-C₁₆ alkyl or dialkyl aminoor further converted to an amide.

Hydroxyl groups of the peptide side chains can be converted to C₁-C₁₆alkoxy or to a C₁-C₁₆ ester using well-recognized techniques. Phenyl andphenolic rings of the peptide side chains can be substituted with one ormore halogen atoms, such as F, Cl, Br or I, or with C₁-C₁₆ alkyl, C₁-C₁₆alkoxy, carboxylic acids and esters thereof, or amides of suchcarboxylic acids. Methylene groups of the peptide side chains can beextended to homologous C₂-C₄ alkylenes. Thiols can be protected with anyone of a number of well-recognized protecting groups, such as acetamidegroups.

Purified: The term purified does not require absolute purity; rather, itis intended as a relative term. Thus, for example, a purified peptidepreparation is one in which the peptide or protein (such as an antibody)is more enriched than the peptide or protein is in its naturalenvironment within a cell. In one embodiment, a preparation is purifiedsuch that the protein or peptide represents at least 50% of the totalpeptide or protein content of the preparation, such as at least 80%, atleast 90%, at least 95% or greater of the total peptide or proteincontent.

Sequence identity: The similarity between amino acid sequences isexpressed in terms of the similarity between the sequences, otherwisereferred to as sequence identity. Sequence identity is frequentlymeasured in terms of percentage identity (or similarity or homology);the higher the percentage, the more similar the two sequences are.Homologs or variants of a polypeptide will possess a relatively highdegree of sequence identity when aligned using standard methods.

Methods of alignment of sequences for comparison are well known in theart. Various programs and alignment algorithms are described in: Smithand Waterman, Adv. Appl. Math. 2:482, 1981; Needleman and Wunsch, J.Mol. Biol. 48:443, 1970; Pearson and Lipman, Proc. Natl. Acad. Sci.U.S.A. 85:2444, 1988; Higgins and Sharp, Gene 73:237, 1988; Higgins andSharp, CABIOS 5:151, 1989; Corpet et al., Nucleic Acids Research16:10881, 1988; and Pearson and Lipman, Proc. Natl. Acad. Sci. U.S.A.85:2444, 1988. Altschul et al., Nature Genet. 6:119, 1994, presents adetailed consideration of sequence alignment methods and homologycalculations.

The NCBI Basic Local Alignment Search Tool (BLAST) (Altschul et al., J.Mol. Biol. 215:403, 1990) is available from several sources, includingthe National Center for Biotechnology Information (NCBI, Bethesda, Md.)and on the internet, for use in connection with the sequence analysisprograms blastp, blastn, blastx, tblastn and tblastx. A description ofhow to determine sequence identity using this program is available onthe NCBI website on the internet.

Homologs and variants of a V_(L) or a V_(H) of an antibody thatspecifically binds a polypeptide are typically characterized bypossession of at least about 75%, for example at least about 80%, 85%,90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identitycounted over the full length alignment with the amino acid sequence ofinterest. Proteins with even greater similarity to the referencesequences will show increasing percentage identities when assessed bythis method, such as at least 80%, at least 85%, at least 90%, at least95%, at least 98%, or at least 99% sequence identity. When less than theentire sequence is being compared for sequence identity, homologs andvariants will typically possess at least 80% sequence identity overshort windows of 10-20 amino acids, and may possess sequence identitiesof at least 85% or at least 90% or 95% depending on their similarity tothe reference sequence. Methods for determining sequence identity oversuch short windows are available at the NCBI website on the internet.One of skill in the art will appreciate that these sequence identityranges are provided for guidance only; it is entirely possible thatstrongly significant homologs could be obtained that fall outside of theranges provided.

Terms used to describe sequence relationships between two or morenucleotide sequences or amino acid sequences include “referencesequence,” “selected from,” “comparison window,” “identical,”“percentage of sequence identity,” “substantially identical,”“complementary,” and “substantially complementary.”

For sequence comparison of nucleic acid sequences, typically onesequence acts as a reference sequence, to which test sequences arecompared. When using a sequence comparison algorithm, test and referencesequences are entered into a computer, subsequence coordinates aredesignated, if necessary, and sequence algorithm program parameters aredesignated. Default program parameters are used. Methods of alignment ofsequences for comparison are well known in the art. Optimal alignment ofsequences for comparison can be conducted, e.g., by the local homologyalgorithm of Smith & Waterman, Adv. Appl. Math. 2:482, 1981, by thehomology alignment algorithm of Needleman & Wunsch, J. Mol. Biol.48:443, 1970, by the search for similarity method of Pearson & Lipman,Proc. Nat'l. Acad. Sci. USA 85:2444, 1988, by computerizedimplementations of these algorithms (GAP, BESTFIT, FASTA, and TFASTA inthe Wisconsin Genetics Software Package, Genetics Computer Group, 575Science Dr., Madison, Wis.), or by manual alignment and visualinspection (see, e.g., Sambrook et al. (Molecular Cloning: A LaboratoryManual, 4^(th) ed, Cold Spring Harbor, N.Y., 2012) and Ausubel et al.(In Current Protocols in Molecular Biology, John Wiley & Sons, New York,through supplement 104, 2013). One example of a useful algorithm isPILEUP. PILEUP uses a simplification of the progressive alignment methodof Feng & Doolittle, J. Mol. Evol. 35:351-360, 1987. The method used issimilar to the method described by Higgins & Sharp, CABIOS 5:151-153,1989. Using PILEUP, a reference sequence is compared to other testsequences to determine the percent sequence identity relationship usingthe following parameters: default gap weight (3.00), default gap lengthweight (0.10), and weighted end gaps. PILEUP can be obtained from theGCG sequence analysis software package, e.g., version 7.0 (Devereaux etal., Nuc. Acids Res. 12:387-395, 1984.

Another example of algorithms that are suitable for determining percentsequence identity and sequence similarity are the BLAST and the BLAST2.0 algorithm, which are described in Altschul et al., J. Mol. Biol.215:403-410, 1990 and Altschul et al., Nucleic Acids Res. 25:3389-3402,1977. Software for performing BLAST analyses is publicly availablethrough the National Center for Biotechnology Information(ncbi.nlm.nih.gov). The BLASTN program (for nucleotide sequences) usesas defaults a word length (W) of 11, alignments (B) of 50, expectation(E) of 10, M=5, N=−4, and a comparison of both strands. The BLASTPprogram (for amino acid sequences) uses as defaults a word length (W) of3, and expectation (E) of 10, and the BLOSUM62 scoring matrix (seeHenikoff & Henikoff, Proc. Natl. Acad. Sci. USA 89:10915, 1989). Anoligonucleotide is a linear polynucleotide sequence of up to about 100nucleotide bases in length.

Skin cancer: A neoplastic tumor of skin tissue that is or has thepotential to be malignant. Melanoma is a skin cancer of transformedmelanocytes (cells that make the pigment melanin). Melanocytes are foundprimary in the skin, but are also present in the bowel and eye. Melanomain the skin includes superficial spreading melanoma, nodular melanoma,acral lentiginous melanoma, and lentigo maligna (melanoma). Any of theabove types may produce melanin or can be amelanotic. Similarly, anysubtype may show desmoplasia (dense fibrous reaction with neurotropism),which is a marker of aggressive behavior and a tendency for localrecurrence. Other melanomas include clear cell sarcoma, mucosal melanomaand uveal melanoma. Melanoma is staged from I to IV. See, for example,Thompson et al. (eds), Textbook of Melanoma: Pathology, Diagnosis andManagement, London: Taylor & Francis, 2004.

Specifically bind: When referring to an antibody, refers to a bindingreaction which determines the presence of a target protein, peptide, orpolysaccharide in the presence of a heterogeneous population of proteinsand other biologics. Thus, under designated conditions, an antibodybinds preferentially to a particular target protein, peptide orpolysaccharide (such as an epitope of TEM8) and does not bind in asignificant amount to other proteins or polysaccharides present in thesample or subject. Specific binding can be determined by methods knownin the art. With reference to an antibody antigen complex, specificbinding of the antigen and antibody has a K_(d) of less than about 10⁻⁷Molar (M), such as less than about 10⁻⁸ M, 10⁻⁹ M, 10⁻¹⁰ M, or even lessthan about 10⁻¹¹ M.

The antibodies disclosed herein specifically bind only to a definedtarget (or multiple targets, in the case of a bispecific antibody).Thus, an antibody that specifically binds to TEM8 is an antibody thatbinds substantially to TEM8, including cells or tissue expressing TEM8,substrate to which the TEM8 is attached, or TEM8 in a biologicalspecimen. It is, of course, recognized that a certain degree ofnon-specific interaction may occur between an antibody or conjugateincluding an antibody (such as an antibody that specifically binds TEM8or conjugate including such antibody) and a non-target (such as a cellthat does not express TEM8). Typically, specific binding results in amuch stronger association between the antibody and protein or cellsbearing the antigen than between the antibody and protein or cellslacking the antigen. Specific binding typically results in greater than2-fold, such as greater than 5-fold, greater than 10-fold, or greaterthan 100-fold increase in amount of bound antibody (per unit time) to aprotein including the epitope or cell or tissue expressing the targetepitope as compared to a protein or cell or tissue lacking this epitope.Specific binding to a protein under such conditions requires an antibodythat is selected for its specificity for a particular protein. A varietyof immunoassay formats are appropriate for selecting antibodies or otherligands specifically immunoreactive with a particular protein. Forexample, solid-phase ELISA immunoassays are routinely used to selectmonoclonal antibodies specifically immunoreactive with a protein. SeeHarlow & Lane, Antibodies, A Laboratory Manual, 2^(nd) ed., Cold SpringHarbor Publications, New York (2013), for a description of immunoassayformats and conditions that can be used to determine specificimmunoreactivity.

Subject: Any mammal, such as humans, non-human primates, pigs, sheep,cows, rodents, and the like. In two non-limiting examples, a subject isa human subject or a murine subject. Thus, the term “subject” includesboth human and veterinary subjects.

T Cell: A white blood cell critical to the immune response. T cellsinclude, but are not limited to, CD4⁺ T cells and CD8⁺ T cells. A CD4⁺ Tlymphocyte is an immune cell that expresses CD4 on its surface. Thesecells, also known as helper T cells, help orchestrate the immuneresponse, including antibody responses as well as killer T cellresponses. Th1 and Th2 cells are functional subsets of helper T cells.Th1 cells secrete a set of cytokines, including interferon-gamma, andwhose principal function is to stimulate phagocyte-mediated defenseagainst infections, especially related to intracellular microbes. Th2cells secrete a set of cytokines, including interleukin (IL)-4 and IL-5,and whose principal functions are to stimulate IgE and eosinophil/mastcell-mediated immune reactions and to downregulate Th1 responses.

Therapeutic agent: Used in a generic sense, it includes treating agents,prophylactic agents, and replacement agents. A therapeutic agent is usedto ameliorate a specific set of conditions in a subject with a diseaseor a disorder.

Therapeutically effective amount: The amount of an agent (such as a TEM8specific antibody or a conjugate including a TEM8 specific antibody)that alone, or together with one or more additional agents, induces thedesired response, such as, for example treatment of a tumor, ortreatment of Anthrax, in a subject. When administered to a subject, adosage will generally be used that will achieve target tissueconcentrations that has been shown to achieve a desired in vitro effect.Ideally, a therapeutically effective amount provides a therapeuticeffect without causing a substantial cytotoxic effect in the subject.

In one example, a desired response is to decrease the size, volume, ornumber (such as metastases) of a tumor in a subject. For example, theagent or agents can decrease the size, volume, or number of tumors by adesired amount, for example by at least 5%, at least 10%, at least 15%,at least 20%, at least 25%, at least 30%, at least 50%, at least 75%, atleast 90%, or at least 95% as compared to a response in the absence ofthe agent.

Several preparations disclosed herein are administered intherapeutically effective amounts. A therapeutically effective amount ofan antibody that specifically binds TEM8 or antigen binding fragmentthereof, or conjugate thereof (or a composition including one or more ofthese molecules) that is administered to a human or veterinary subjectwill vary depending upon a number of factors associated with thatsubject, for example the overall health of the subject. Atherapeutically effective amount can be determined by varying the dosageand measuring the resulting therapeutic response, such as the regressionof a tumor. Therapeutically effective amounts also can be determinedthrough various in vitro, in vivo or in situ immunoassays. The disclosedagents can be administered in a single dose, or in several doses, asneeded to obtain the desired response. However, the therapeuticallyeffective amount of can be dependent on the source applied, the subjectbeing treated, the severity and type of the condition being treated, andthe manner of administration.

Toxin: An effector molecule that induces cytotoxicity when it contacts acell. Specific, non-limiting examples of toxins include, but are notlimited to, abrin, ricin, auristatins (such as monomethyl auristatin E(MMAE; see for example, Francisco et al., Blood, 102: 1458-1465, 2003))and monomethyl auristatin F (MMAF; see, for example, Doronina et al.,BioConjugate Chem., 17: 114-124, 2006), maytansinoids (such as DM1; see,for example, Phillips et al., Cancer Res., 68:9280-9290, 2008),Pseudomonas exotoxin (PE, such as PE35, PE37, PE38, and PE40),diphtheria toxin (DT), botulinum toxin, saporin, restrictocin orgelonin, or modified toxins thereof, or other toxic agents that directlyor indirectly inhibit cell growth or kill cells. For example, PE and DTare highly toxic compounds that typically bring about death throughliver toxicity. PE and DT, however, can be modified into a form for useas an immunotoxin by removing the native targeting component of thetoxin (such as the domain Ia of PE and the B chain of DT) and replacingit with a different targeting moiety, such as an antibody.

Transformed: A transformed cell is a cell into which a nucleic acidmolecule has been introduced by molecular biology techniques. As usedherein, the term transformation encompasses all techniques by which anucleic acid molecule might be introduced into such a cell, includingtransfection with viral vectors, transformation with plasmid vectors,and introduction of DNA by electroporation, lipofection, and particlegun acceleration.

Tumor burden: The total volume, number, metastasis, or combinationsthereof of tumor or tumors in a subject.

Tumor Endothelial Marker 8 (TEM8): A protein also known as Anthrax ToxinReceptor 1 (ANTXR1). TEM8 is a cell-surface glycoprotein originallyidentified based on its over-expression in the endothelial cells thatline the tumor vasculature of human colorectal cancer (St Croix et al.,Science, 289(5482): 1197-1202, 2000). Unlike vascular endothelial growthfactor (VEGF), VEGF receptor (VEGFR), and many other key angiogenesisregulators, TEM8 is not required for developmental angiogenesis, woundhealing, or normal physiological angiogenesis of the corpus luteum (StCroix et al., Science, 289(5482):1197-1202, 2000; Nanda et al., CancerRes., 64(3):817-820, 2004). TEM8 is up-regulated on tumor vessels ofvarious tumor types in both mice and humans (Nanda et al., Cancer Res.,64(3):817-820, 2004; Carson-Walter et al., Cancer Res.,61(18):6649-6655, 2001), and in some tumors is also expressed by thetumor cells themselves (Carson-Walter et al. Cancer Res.,61(18):6649-6655, 2001; Yang et al., Biochim Biophys Acta,1813(1):39-49, 2011). TEM8 also functions as a cell-surface receptor forAnthrax toxin, and shares 58% amino acid identify with CMG2 (also knownas ANTXR2), which is a second receptor for Anthrax toxin protein (Scobieet al., Proc. Natl. Acad. Sci. U.S.A., 100(9):5170-5174, 2003).

TEM8 protein sequence is known (see, for example, GENBANK® Accession No.NP_115584.1, incorporated by reference herein as present in the databaseon Sep. 10, 2013). Additionally, exemplary nucleic acid sequencesencoding TEM8 protein are known (see, for example, GENBANK® AccessionNo. NM_032208.2, incorporated by reference herein as present in thedatabase on Sep. 10, 2013). In one example, TEM8 is a polypeptide havingan amino acid sequence set forth as SEQ ID NO: 10.

Tumor microenvironment: The cellular environment in which a tumorexists, including surrounding blood vessels, immune cells, fibroblasts,signaling molecules, and the extracellular matrix (ECM), includingstromal cells. Tumors can influence the microenvironment by releasingextracellular signals, promoting pathological angiogenesis and inducingperipheral immune tolerance, while the immune cells in themicroenvironment can affect the growth and evolution of cancerous cells,such as in immuno-editing.

Under conditions sufficient for: A phrase that is used to describe anyenvironment that permits a desired activity. In one example the desiredactivity is formation of an immune complex. In particular examples thedesired activity is treatment of a tumor.

Vector: A nucleic acid molecule as introduced into a host cell, therebyproducing a transformed host cell. A vector may include nucleic acidsequences that permit it to replicate in a host cell, such as an originof replication. A vector may also include one or more selectable markergenes and other genetic elements known in the art.

II. Description of Several Embodiments

Isolated monoclonal antibodies and antigen binding fragments thereofthat specifically bind an epitope on TEM8 protein are provided. Theantibodies and antigen binding fragments can be fully human. In severalembodiments, the antibodies and antigen binding fragments can be used toneutralize HIV-1 infection. Also disclosed herein are compositionsincluding the antibodies and antigen binding fragments and apharmaceutically acceptable carrier. Nucleic acids encoding theantibodies or antigen binding fragments, expression vectors includingthese nucleic acids, and isolated host cells that express the nucleicacids are also provided.

Compositions comprising the monoclonal antibodies specific for TEM8 canbe used for research, diagnostic and therapeutic purposes. For example,the monoclonal antibodies can be used to diagnose or treat a subjecthaving pathogenic angiogenesis.

A. Antibodies and Antigen Binding Fragments

Isolated monoclonal antibodies and antigen binding fragments thatspecifically bind an epitope on TEM8 protein and are neutralizing areprovided. In several embodiments, the antibodies and antigen bindingfragments can neutralize a biological function or property of TEM8protein in vivo, including, but not limited to, a reduction and/orinhibition of pathological angiogenesis, a reduction and/or inhibitionof tumor growth, or a reduction and/or inhibition of tumor metastasis.

In several embodiments, the monoclonal antibodies include a heavy chaincomprising a heavy chain complementarity determining region (HCDR)1, aHCDR2 and an HCDR3, and a light chain comprising a light chaincomplementarity determining region (LCDR) 1, LCDR2 and LCDR3. Thedisclosed antibodies specifically bind to an epitope of TEM8 and areneutralizing. In some embodiments, the TEM8 specific antibodies includea variable heavy (V_(H)) and a variable light (V_(L)) chain andspecifically bind TEM8. In several embodiments, the antibody or antigenbinding fragment thereof includes heavy and light chain variable regionsincluding the HCDR1, HCDR2, and HCDR3, and LCDR1, LCDR2, and LCDR3,respectively, of one of the m825, m822, m830, or m863 antibodies.

The discussion of monoclonal antibodies below refers to isolatedmonoclonal antibodies that include heavy and light chain variabledomains including at least one complementarity determining region (CDR),such as a CDR1, CDR2 and CDR3. The person of ordinary skill in the artwill understand that various CDR numbering schemes (such as the Kabat,Chothia or IMGT numbering schemes) can be used to determine CDRpositions. The amino acid sequence and the CDR positions of the heavyand light chain of the m825, m822, m830, and m863 monoclonal antibodiesaccording to the IMGT and Kabat numbering schemes are shown in Table 1(IMGT) and Table 2 (Kabat). The person of skill in the art will readilyunderstand use of various CDR numbering schemes when referencingparticular amino acids of the antibodies disclosed herein.

TABLE 1 IMGT CDR sequences of TEM8 specific antibodies m825 SEQ ID NO: 1A.A. Sequence SEQ ID NO: 2 A.A. Sequence HCDR1 26-33 GYTFSSYA LCDR126-31 NLRDFY HCDR2 51-58 IIPIFGTT LCDR2 49-51 GKN HCDR3 97-106ARDTDYMFDY LCDR3 88-97 SSRDNSKHVV m822 SEQ ID NO: 3 A.A. Sequence SEQ IDNO: 4 A.A. Sequence HCDR1 26-33 GYTFSSYA LCDR1 26-31 NLRDFY HCDR2 51-58IIPIFGTA LCDR2 49-51 GKN HCDR3 97-106 ARDTDYMFDY LCDR3 88-97 SSRDNSKHVVm830 SEQ ID NO: 5 A.A. Sequence SEQ ID NO: 6 A.A. Sequence HCDR1 26-33GFTFSTYT LCDR1 27-32 QTISRY HCDR2 51-58 ISNDGSNK LCDR2 50-52 AAS HCDR397-110 VRGSSWYRGNWFDP LCDR3 89-97 QQTYSPPIT m863 SEQ ID NO: 7 A.A.Sequence SEQ ID NO: 8 A.A. Sequence HCDR1 26-33 GYTFTGYY LCDR1 27-32RAISRY HCDR2 51-58 INPTSGST LCDR2 50-52 AAS HCDR3 97-110 VRDPGSPKWLAFDPLCDR3 89-97 QQTYSPPIT

In some embodiments, the antibody includes IMGT CDRs, such as thoselisted in Table 1. For example, in some embodiments, the antibodyincludes a heavy chain variable region including a HCDR1, HCDR2, and/orHCDR3 including amino acids 26-33, 51-58, and 97-106 of SEQ ID NO: 1,respectively. In further embodiments, the antibody includes a heavychain variable region including a HCDR1, HCDR2, and/or HCDR3 includingamino acids 26-33, 51-58, and 97-106 of SEQ ID NO: 3, respectively. Inadditional embodiments, the antibody includes a heavy chain variableregion including a HCDR1, HCDR2, and/or HCDR3 including amino acids26-33, 51-58, and 97-110 of SEQ ID NO: 5, respectively. In moreembodiments, the antibody includes a heavy chain variable regionincluding a HCDR1, HCDR2, and/or HCDR3 including amino acids 26-33,51-58, and 97-110 of SEQ ID NO: 7, respectively.

In some embodiments, the antibody includes a light chain variable regionincluding a LCDR1, LCDR2, and/or LCDR3 including amino acids 26-31,49-51, and 88-97 of SEQ ID NO: 2, respectively. In further embodiments,the antibody includes a light chain variable region including a LCDR1,LCDR2, and/or LCDR3 including amino acids 26-31, 49-51, and 88-97 of SEQID NO: 4, respectively. In additional embodiments, the antibody includesa light chain variable region including a LCDR1, LCDR2, and/or LCDR3including amino acids 27-32, 50-52, and 89-97 of SEQ ID NO: 6,respectively. In more embodiments, the antibody includes a light chainvariable region including a LCDR1, LCDR2, and/or LCDR3 including aminoacids 27-32, 50-52, and 89-97 of SEQ ID NO: 8, respectively.

In some embodiments, the antibody includes a heavy chain variable regionincluding a HCDR1, HCDR2, and HCDR3 including amino acids 26-33, 51-58,and 97-106 of SEQ ID NO: 1, respectively, and a light chain variableregion including a LCDR1, LCDR2, and LCDR3 including amino acids 26-31,49-51, and 88-97 of SEQ ID NO: 2, respectively. In further embodiments,the antibody includes a heavy chain variable region including a HCDR1,HCDR2, and HCDR3 including amino acids 26-33, 51-58, and 97-106 of SEQID NO: 3, respectively, and a light chain variable region including aLCDR1, LCDR2, and LCDR3 including amino acids 26-31, 49-51, and 88-97 ofSEQ ID NO: 4, respectively. In additional embodiments, the antibodyincludes a heavy chain variable region including a HCDR1, HCDR2, andHCDR3 including amino acids 26-33, 51-58, and 97-110 of SEQ ID NO: 5,respectively, and a light chain variable region including a LCDR1,LCDR2, and LCDR3 including amino acids 27-32, 50-52, and 89-97 of SEQ IDNO: 6, respectively. In more embodiments, the antibody includes a heavychain variable region including a HCDR1, HCDR2, and HCDR3 includingamino acids 26-33, 51-58, and 97-110 of SEQ ID NO: 7, respectively, anda light chain variable region including a LCDR1, LCDR2, and LCDR3including amino acids 27-32, 50-52, and 89-97 of SEQ ID NO: 8,respectively.

TABLE 2 Kabat CDR sequences of TEM8 specific antibodies m825 SEQ ID NO:1 A.A. Sequence SEQ ID NO: 2 A.A. Sequence HCDR1 26-32 GYTFSSY LCDR123-33 QGDNLRDFYAS HCDR2 52-57 IPIFGT LCDR2 49-55 GKNRRPS HCDR3 99-106DTDYMFDY LCDR3 88-97 SSRDNSKHVV m822 SEQ ID NO: 3 A.A. Sequence SEQ IDNO: 4 A.A. Sequence HCDR1 26-32 GYTFSSY LCDR1 23-33 QGDNLRDFYAS HCDR252-57 IPIFGT LCDR2 49-55 GKNRRPS HCDR3 99-106 DTDYMFDY LCDR3 88-97SSRDNSKHVV m830 SEQ ID NO: 5 A.A. Sequence SEQ ID NO: 6 A.A. SequenceHCDR1 26-32 GFTFSTY LCDR1 24-34 RASQTISRYLN HCDR2 52-57 SNDGSN LCDR250-56 AASSLQS HCDR3 99-110 GSSWYRGNWFDP LCDR3 89-97 QQTYSPPIT m863 SEQID NO: 7 A.A. Sequence SEQ ID NO: 8 A.A. Sequence HCDR1 26-32 GYTFTGYLCDR1 24-34 RASRAISRYLN HCDR2 52-57 NPTSGS LCDR2 50-56 AASSLQS HCDR399-110 DPGSPKWLAFDP LCDR3 89-97 QQTYSPPIT

In some embodiments, the antibody includes Kabat CDRs, such as thoselisted in Table 2. In some embodiments, the antibody includes a heavychain variable region including a HCDR1, HCDR2, and/or HCDR3 includingamino acids 26-32, 52-57, and 99-106 of SEQ ID NO: 1, respectively. Infurther embodiments, the antibody includes a heavy chain variable regionincluding a HCDR1, HCDR2, and/or HCDR3 including amino acids 26-32,52-57, and 99-106 of SEQ ID NO: 3, respectively. In additionalembodiments, the antibody includes a heavy chain variable regionincluding a HCDR1, HCDR2, and/or HCDR3 including amino acids 26-32,52-57, and 99-110 of SEQ ID NO: 5, respectively. In more embodiments,the antibody includes a heavy chain variable region including a HCDR1,HCDR2, and/or HCDR3 including amino acids 26-32, 52-57, and 99-110 ofSEQ ID NO: 7, respectively.

In some embodiments, the antibody includes a light chain variable regionincluding a LCDR1, LCDR2, and/or LCDR3 including amino acids 23-33,49-55, and 88-97 of SEQ ID NO: 2, respectively. In further embodiments,the antibody includes a light chain variable region including a LCDR1,LCDR2, and/or LCDR3 including amino acids 23-33, 49-55, and 88-97 of SEQID NO: 4, respectively. In additional embodiments, the antibody includesa light chain variable region including a LCDR1, LCDR2, and/or LCDR3including amino acids 24-34, 50-56, and 89-97 of SEQ ID NO: 6,respectively. In more embodiments, the antibody includes a light chainvariable region including a LCDR1, LCDR2, and/or LCDR3 including aminoacids 24-34, 50-56, and 89-97 of SEQ ID NO: 8, respectively.

In some embodiments, the antibody includes a heavy chain variable regionincluding a HCDR1, HCDR2, and HCDR3 including amino acids 26-32, 52-57,and 99-106 of SEQ ID NO: 1, respectively, and a light chain variableregion including a LCDR1, LCDR2, and LCDR3 including amino acids 23-33,49-55, and 88-97 of SEQ ID NO: 2, respectively. In further embodiments,the antibody includes a heavy chain variable region including a HCDR1,HCDR2, and HCDR3 including amino acids 26-32, 52-57, and 99-106 of SEQID NO: 3, respectively, and a light chain variable region including aLCDR1, LCDR2, and LCDR3 including amino acids 23-33, 49-55, and 88-97 ofSEQ ID NO: 4, respectively. In additional embodiments, the antibodyincludes a heavy chain variable region including a HCDR1, HCDR2, andHCDR3 including amino acids 26-32, 52-57, and 99-110 of SEQ ID NO: 5,respectively, and a light chain variable region including a LCDR1,LCDR2, and LCDR3 including amino acids 24-34, 50-56, and 89-97 of SEQ IDNO: 6, respectively. In more embodiments, the antibody includes a heavychain variable region including a HCDR1, HCDR2, and HCDR3 includingamino acids 26-32, 52-57, and 99-110 of SEQ ID NO: 7, respectively, anda light chain variable region including a LCDR1, LCDR2, and LCDR3including amino acids 24-34, 50-56, and 89-97 of SEQ ID NO: 8,respectively.

In some embodiments, the antibody includes a heavy chain variable regionincluding an amino acid sequence at least 95%, 96%, 97%, 98%, or 99%identical to the amino acid sequence set forth as one of SEQ ID NO: 1(m825 VH), SEQ ID NO: 3 (m822 VH), SEQ ID NO: 5 (m830 VH), or SEQ ID NO:7 (m863 VH). In more embodiments, the antibody includes a light chainvariable region including an amino acid sequence at least 95%, 96%, 97%,98%, or 99% identical to the amino acid sequence set forth as one of SEQID NO: 2 (m825 VL), SEQ ID NO: 4 (m822 VL), SEQ ID NO: 6 (m830 VL), orSEQ ID NO: 8 (m863 VL).

In additional embodiments, the antibody includes a heavy chain variableregion including an amino acid sequence at least 95%, 96%, 97%, 98%, or99% identical to the amino acid sequence set forth as SEQ ID NO: 1 (m825VH), and a light chain variable region including an amino acid sequenceat least 95%, 96%, 97%, 98%, or 99% identical to the amino acid sequenceset forth as SEQ ID NO: 2 (m825 VL). In further embodiments, theantibody includes a heavy chain variable region including an amino acidsequence at least 95%, 96%, 97%, 98%, or 99% identical to the amino acidsequence set forth as SEQ ID NO: 3 (m822 VH), and a light chain variableregion including an amino acid sequence at least 95%, 96%, 97%, 98%, or99% identical to the amino acid sequence set forth as SEQ ID NO: 4 (m822VL). In additional embodiments, the antibody includes a heavy chainvariable region including an amino acid sequence at least 95%, 96%, 97%,98%, or 99% identical to the amino acid sequence set forth as SEQ ID NO:5 (m830 VH), and a light chain variable region including an amino acidsequence at least 95%, 96%, 97%, 98%, or 99% identical to the amino acidsequence set forth as SEQ ID NO: 6 (m830 VL). In more embodiments, theantibody includes a heavy chain variable region including an amino acidsequence at least 95%, 96%, 97%, 98%, or 99% identical to the amino acidsequence set forth as SEQ ID NO: 7 (m863 VH), and a light chain variableregion including an amino acid sequence at least 95%, 96%, 97%, 98%, or99% identical to the amino acid sequence set forth as SEQ ID NO: 8 (m863VL).

In additional embodiments, the antibody includes a heavy chain variableregion including the amino acid sequence set forth as one of SEQ ID NO:1 (m825 VH), SEQ ID NO: 3 (m822 VH), SEQ ID NO: 5 (m830 VH), or SEQ IDNO: 7 (m863 VH). In more embodiments, the antibody includes a lightchain variable region including the amino acid sequence set forth as oneof SEQ ID NO: 2 (m825 VL), SEQ ID NO: 4 (m822 VL), SEQ ID NO: 6 (m830VL), or SEQ ID NO: 8 (m863 VL).

In some embodiments, the antibody includes a heavy chain variable regionincluding the amino acid sequence set forth as SEQ ID NO: 1 (m825 VH),and a light chain variable region including the amino acid sequence setforth as SEQ ID NO: 2 (m825 VL). In further embodiments, the antibodyincludes a heavy chain variable region including the amino acid sequenceset forth as SEQ ID NO: 3 (m822 VH), and a light chain variable regionincluding the amino acid sequence set forth as SEQ ID NO: 4 (m822 VL).In additional embodiments, the antibody includes a heavy chain variableregion including the amino acid sequence set forth as SEQ ID NO: 5 (m830VH), and a light chain variable region including the amino acid sequenceset forth as SEQ ID NO: 6 (m830 VL). In more embodiments, the antibodyincludes a heavy chain variable region including the amino acid sequenceset forth as SEQ ID NO: 7 (m863 VH), and a light chain variable regionincluding the amino acid sequence set forth as SEQ ID NO: 8 (m863 VL).

1. Additional Description of Antibodies and Antigen Binding Fragments

The antibody or antigen binding fragment can be a human antibody orfragment thereof. Chimeric antibodies are also provided. The antibody orantigen binding fragment can include any suitable framework region, suchas (but not limited to) a human framework region. Human frameworkregions, and mutations that can be made in a human antibody frameworkregions, are known in the art (see, for example, in U.S. Pat. No.5,585,089, which is incorporated herein by reference). Alternatively, aheterologous framework region, such as, but not limited to a mouseframework region, can be included in the heavy or light chain of theantibodies. (See, for example, Jones et al., Nature 321:522, 1986;Riechmann et al., Nature 332:323, 1988; Verhoeyen et al., Science239:1534, 1988; Carter et al., Proc. Natl. Acad. Sci. U.S.A. 89:4285,1992; Sandhu, Crit. Rev. Biotech. 12:437, 1992; and Singer et al., J.Immunol. 150:2844, 1993.)

The antibody can be of any isotype. The antibody can be, for example, anIgM or an IgG antibody, such as IgG₁, IgG₂, IgG₃, or IgG₄. The class ofan antibody that specifically binds TEM8 can be switched with another.In one aspect, a nucleic acid molecule encoding V_(L) or V_(H) isisolated using methods well-known in the art, such that it does notinclude any nucleic acid sequences encoding the constant region of thelight or heavy chain, respectively. In particular examples, the V_(H)amino acid sequence is set forth as one of SEQ ID NOs: 1, 3, 5, 7. Inother examples, the V_(L) amino acid sequence is set forth as one of SEQID NOs: 2, 4, 6, 8. In a non-limiting example, the V_(H) amino acidsequence is set forth as SEQ ID NO: 1, and the V_(L) amino acid sequenceis set forth as SEQ ID NO: 2. A nucleic acid molecule encoding V_(L) orV_(H) is then operatively linked to a nucleic acid sequence encoding aC_(L) or C_(H) from a different class of immunoglobulin molecule. Thiscan be achieved using a vector or nucleic acid molecule that comprises aC_(L) or C_(H) chain, as known in the art. For example, an antibody thatspecifically binds TEM8, that was originally IgM may be class switchedto an IgG. Class switching can be used to convert one IgG subclass toanother, such as from IgG₁ to IgG₂, IgG₃, or IgG₄.

In some examples, the disclosed antibodies are oligomers of antibodies,such as dimers, trimers, tetramers, pentamers, hexamers, septamers,octomers and so on.

(a) Binding Affinity

In several embodiments, the antibody or antigen binding fragment canspecifically bind TEM8 protein with an affinity (e.g., measured byK_(d)) of no more than 1.0×10⁻⁸ M, no more than 5.0×10⁻⁸ M, no more than1.0×10⁻⁹ M, no more than 5.0×10⁻⁹ M, no more than 1.0×10⁻¹⁰ M, no morethan 5.0×10⁻¹⁰ M, or no more than 1.0×10⁻¹¹ M. K_(d) can be measured,for example, by a radiolabeled antigen binding assay (RIA) performedwith the Fab version of an antibody of interest and its antigen usingknown methods. In one assay, solution binding affinity of Fabs forantigen is measured by equilibrating Fab with a minimal concentration of(¹²⁵I)-labeled antigen in the presence of a titration series ofunlabeled antigen, then capturing bound antigen with an anti-Fabantibody-coated plate (see, e.g., Chen et al., J. Mol. Biol. 293:865-881(1999)). To establish conditions for the assay, MICROTITER® multi-wellplates (Thermo Scientific) are coated overnight with 5 μg/ml of acapturing anti-Fab antibody (Cappel Labs) in 50 mM sodium carbonate (pH9.6), and subsequently blocked with 2% (w/v) bovine serum albumin in PBSfor two to five hours at room temperature (approximately 23° C.). In anon-adsorbent plate (Nunc #269620). 100 μM or 26 pM [¹²⁵I]-antigen aremixed with serial dilutions of a Fab of interest (e.g., consistent withassessment of the anti-VEGF antibody, Fab-12, in Presta et al., CancerRes. 57:4593-4599 (1997)). The Fab of interest is then incubatedovernight; however, the incubation may continue for a longer period(e.g., about 65 hours) to ensure that equilibrium is reached.Thereafter, the mixtures are transferred to the capture plate forincubation at room temperature (e.g., for one hour). The solution isthen removed and the plate washed eight times with 0.1% polysorbate 20(TWEEN-20®) in PBS. When the plates have dried, 150 μl/well ofscintillant (MICROSCINT-20™; Packard) is added, and the plates arecounted on a TOPCOUNT™ gamma counter (Packard) for ten minutes.Concentrations of each Fab that give less than or equal to 20% ofmaximal binding are chosen for use in competitive binding assays.

In another assay, K_(d) can be measured using surface plasmon resonanceassays using a BIACORE®-2000 or a BIACORE®-3000 (BIAcore. Inc.,Piscataway. N.J.) at 25° C. with immobilized antigen CM5 chips at ˜10response units (RU). Briefly, carboxymethylated dextran biosensor chips(CM5, BIACORE®, Inc.) are activated withN-ethyl-N′-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC) andN-hydroxysuccinimide (NHS) according to the supplier's instructions.Antigen is diluted with 10 mM sodium acetate, pH 4.8, to 5 μg/ml (˜0.2μM) before injection at a flow rate of 5 l/minute to achieveapproximately 10 response units (RU) of coupled protein. Following theinjection of antigen, 1 M ethanolamine is injected to block unreactedgroups. For kinetics measurements, two-fold serial dilutions of Fab(0.78 nM to 500 nM) are injected in PBS with 0.05% polysorbate 20(TWEEN-20™) surfactant (PBST) at 25° C. at a flow rate of approximately25 l/min. Association rates (k_(on)) and dissociation rates (k_(off))are calculated using a simple one-to-one Langmuir binding model(BIACORE® Evaluation Software version 3.2) by simultaneously fitting theassociation and dissociation sensorgrams. The equilibrium dissociationconstant (Kd) is calculated as the ratio k_(off)/k_(on). See, e.g., Chenet al., J. Mol. Biol. 293:865-881 (1999). If the on-rate exceeds 106 M⁻¹s⁻¹ by the surface plasmon resonance assay above, then the on-rate canbe determined by using a fluorescent quenching technique that measuresthe increase or decrease in fluorescence emission intensity(excitation=295 nm; emission=340 nm, 16 nm band-pass) at 25° C. of a 20nM anti-antigen antibody (Fab form) in PBS, pH 7.2, in the presence ofincreasing concentrations of antigen as measured in a spectrometer, suchas a stop-flow equipped spectrophometer (Aviv Instruments) or a8000-series SLM-AMINCO™ spectrophotometer (ThermoSpectronic) with astirred cuvette.

(b) Multispecific Antibodies

In some embodiments, the antibody or antigen binding fragment isincluded on a multispecific antibody, such as a bi-specific antibody.Such multispecific antibodies can be produced by known methods, such ascrosslinking two or more antibodies, antigen binding fragments (such asscFvs) of the same type or of different types. Exemplary methods ofmaking multispecific antibodies include those described in PCT Pub. No.WO2013/163427, which is incorporated by reference herein in itsentirety. Suitable crosslinkers include those that areheterobifunctional, having two distinctly reactive groups separated byan appropriate spacer (such as m-maleimidobenzoyl-N-hydroxysuccinimideester) or homobifunctional (such as disuccinimidyl suberate). Suchlinkers are available from Pierce Chemical Company, Rockford, Ill.

In some embodiments, the antibody or antigen binding fragment isincluded on a bispecific antibody that that specifically binds to TEM8protein and further specifically binds to CD3. Examples of CD3 bindingdomains that can be included on the bispecific antibody or antigenbinding fragment are known and include those disclosed in PCT Pub. No.WO2013/163427, which is incorporated by reference herein in itsentirety.

Various types of multi-specific antibodies are known. Bispecific singlechain antibodies can be encoded by a single nucleic acid molecule.Examples of bispecific single chain antibodies, as well as methods ofconstructing such antibodies are known in the art (see, e.g., U.S. Pat.Nos. 8,076,459, 8,017,748, 8,007,796, 7,919,089, 7,820,166, 7,635,472,7,575,923, 7,435,549, 7,332,168, 7,323,440, 7,235,641, 7,229,760,7,112,324, 6,723,538, incorporated by reference herein). Additionalexamples of bispecific single chain antibodies can be found in PCTapplication No. WO 99/54440; Mack, J. Immunol., 158:3965-3970, 1997;Mack, PNAS, 92:7021-7025, 1995; Kufer, Cancer Immunol. Immunother.,45:193-197, 1997; Loffler, Blood, 95:2098-2103, 2000; and Bruhl, J.Immunol., 166:2420-2426, 2001. Production of bispecific Fab-scFv(“bibody”) molecules are described, for example, in Schoonjans et al.(J. Immunol. 165:7050-57, 2000) and Willems et al. (J Chromatogr BAnalyt Technol Biomed Life Sci. 786:161-76, 2003). For bibodies, a scFvmolecule can be fused to one of the VL-CL (L) or VH-CH1 chains, e.g., toproduce a bibody one scFv is fused to the C-term of a Fab chain.

(c) Fragments

Antigen binding fragments are encompassed by the present disclosure,such as Fab, F(ab′)₂, and Fv which include a heavy chain and light chainvariable region and specifically bind TEM8 protein.

These antibody fragments retain the ability to selectively bind with theantigen and are “antigen-binding” fragments. These fragments include:

(1) Fab, the fragment which contains a monovalent antigen-bindingfragment of an antibody molecule, can be produced by digestion of wholeantibody with the enzyme papain to yield an intact light chain and aportion of one heavy chain;

(2) Fab′, the fragment of an antibody molecule can be obtained bytreating whole antibody with pepsin, followed by reduction, to yield anintact light chain and a portion of the heavy chain; two Fab′ fragmentsare obtained per antibody molecule;

(3) (Fab′)₂, the fragment of the antibody that can be obtained bytreating whole antibody with the enzyme pepsin without subsequentreduction; F(ab′)₂ is a dimer of two Fab′ fragments held together by twodisulfide bonds;

(4) Fv, a genetically engineered fragment containing the variable regionof the light chain and the variable region of the heavy chain expressedas two chains; and

(5) Single chain antibody (such as scFv), defined as a geneticallyengineered molecule containing the variable region of the light chain,the variable region of the heavy chain, linked by a suitable polypeptidelinker as a genetically fused single chain molecule. A scFv is a fusionprotein in which a light chain variable region of an immunoglobulin anda heavy chain variable region of an immunoglobulin are bound by a linker(see, e.g., Ahmad et al., Clin. Dev. Immunol., 2012,doi:10.1155/2012/980250; Marbry, IDrugs, 13:543-549, 2010). Theintramolecular orientation of the V_(H)-domain and the V_(L)-domain in ascFv, is not decisive for the provided antibodies (e.g., for theprovided multispecific antibodies). Thus, scFvs with both possiblearrangements (V_(H)-domain-linker domain-V_(L)-domain;V_(L)-domain-linker domain-V_(H)-domain) may be used.

(6) A dimer of a single chain antibody (scFV₂), defined as a dimer of ascFV. This has also been termed a “miniantibody.”

Methods of making these fragments are known in the art (see for example,Harlow and Lane, Antibodies: A Laboratory Manual, 2^(nd), Cold SpringHarbor Laboratory, New York, 2013).

In a further group of embodiments, the antibody binding fragment can bean Fv antibody, which is typically about 25 kDa and contain a completeantigen-binding site with three CDRs per each heavy chain and each lightchain. To produce Fv antibodies, the V_(H) and the V_(L) can beexpressed from two individual nucleic acid constructs in a host cell. Ifthe V_(H) and the V_(L) are expressed non-contiguously, the chains ofthe Fv antibody are typically held together by noncovalent interactions.However, these chains tend to dissociate upon dilution, so methods havebeen developed to crosslink the chains through glutaraldehyde,intermolecular disulfides, or a peptide linker. Thus, in one example,the Fv can be a disulfide stabilized Fv (dsFv), wherein the heavy chainvariable region and the light chain variable region are chemicallylinked by disulfide bonds.

In an additional example, the Fv fragments comprise V_(H) and V_(L)chains connected by a peptide linker. These single-chain antigen bindingproteins (scFv) are prepared by constructing a nucleic acid moleculeencoding the V_(H) and V_(L) domains connected by an oligonucleotide.The nucleic acid molecule is inserted into an expression vector, whichis subsequently introduced into a host cell such as a mammalian cell.The recombinant host cells synthesize a single polypeptide chain with alinker peptide bridging the two V domains. Methods for producing scFvsare known in the art (see Whitlow et al., Methods: a Companion toMethods in Enzymology, Vol. 2, page 97, 1991; Bird et al., Science242:423, 1988; U.S. Pat. No. 4,946,778; Pack et al., Bio/Technology11:1271, 1993; Ahmad et al., Clin. Dev. Immunol., 2012, doi:10.1155/2012/980250; Marbry, IDrugs, 13:543-549, 2010). Dimers of asingle chain antibody (scFV₂), are also contemplated.

Antigen binding fragments can be prepared by proteolytic hydrolysis ofthe antibody or by expression in a host cell (such as an E. coli cell)of DNA encoding the fragment. Antigen binding fragments can also beobtained by pepsin or papain digestion of whole antibodies byconventional methods. For example, antigen binding fragments can beproduced by enzymatic cleavage of antibodies with pepsin to provide a 5Sfragment denoted F(ab′)₂. This fragment can be further cleaved using athiol reducing agent, and optionally a blocking group for the sulfhydrylgroups resulting from cleavage of disulfide linkages, to produce 3.5SFab′ monovalent fragments. Alternatively, an enzymatic cleavage usingpepsin produces two monovalent Fab′ fragments and an Fc fragmentdirectly (see U.S. Pat. No. 4,036,945 and U.S. Pat. No. 4,331,647, andreferences contained therein; Nisonhoff et al., Arch. Biochem. Biophys.89:230, 1960; Porter, Biochem. J. 73:119, 1959; Edelman et al., Methodsin Enzymology, Vol. 1, page 422, Academic Press, 1967; and Coligan etal. at sections 2.8.1-2.8.10 and 2.10.1-2.10.4).

Other methods of cleaving antibodies, such as separation of heavy chainsto form monovalent light-heavy chain fragments, further cleavage offragments, or other enzymatic, chemical, or genetic techniques may alsobe used, so long as the fragments bind to the antigen that is recognizedby the intact antibody.

Antigen binding single V_(H) domains, called domain antibodies (dAb),have also been identified from a library of murine V_(H) genes amplifiedfrom genomic DNA of immunized mice (Ward et al. Nature 341:544-546,1989). Human single immunoglobulin variable domain polypeptides capableof binding antigen with high affinity have also been described (see, forexample, PCT Publication Nos. WO 2005/035572 and WO 2003/002609). TheCDRs disclosed herein can also be included in a dAb.

In some embodiments, one or more of the heavy and/or light chaincomplementarity determining regions (CDRs) from a disclosed antibody isexpressed on the surface of another protein, such as a scaffold protein.The expression of domains of antibodies on the surface of a scaffoldingprotein are known in the art (see e.g. Liu et al., J. Virology 85(17):8467-8476, 2011). Such expression creates a chimeric protein thatretains the binding for TEM8. In some specific embodiments, one or moreof the heavy chain CDRs is grafted onto a scaffold protein, such as oneor more of heavy chain CDR1, CDR2, and/or CDR3. One or more CDRs canalso be included in a diabody or another type of single chain antibodymolecule.

(d) Variants

In certain embodiments, amino acid sequence variants of the antibodiesprovided herein are contemplated. For example, it may be desirable toimprove the binding affinity and/or other biological properties of theantibody. Amino acid sequence variants of an antibody may be prepared byintroducing appropriate modifications into the nucleotide sequenceencoding the antibody, or by peptide synthesis. Such modificationsinclude, for example, deletions from, and/or insertions into and/orsubstitutions of residues within the amino acid sequences of theantibody. Any combination of deletion, insertion, and substitution canbe made to arrive at the final construct, provided that the finalconstruct possesses the desired characteristics, e.g., antigen-binding.

In certain embodiments, antibody variants having one or more amino acidsubstitutions are provided. Sites of interest for substitutionalmutagenesis include the CDRs and the framework regions. Amino acidsubstitutions may be introduced into an antibody of interest and theproducts screened for a desired activity, e.g., retained/improvedantigen binding, decreased immunogenicity, or improved ADCC or CDC.

The variants typically retain amino acid residues necessary for correctfolding and stabilizing between the V_(H) and the V_(L) regions, andwill retain the charge characteristics of the residues in order topreserve the low pI and low toxicity of the molecules. Amino acidsubstitutions can be made in the V_(H) and the V_(L) regions to increaseyield. Conservative amino acid substitution tables providingfunctionally similar amino acids are well known to one of ordinary skillin the art. The following six groups are examples of amino acids thatare considered to be conservative substitutions for one another:

-   -   1) Alanine (A), Serine (S), Threonine (T);    -   2) Aspartic acid (D), Glutamic acid (E);    -   3) Asparagine (N), Glutamine (Q);    -   4) Arginine (R), Lysine (K);    -   5) Isoleucine (I), Leucine (L), Methionine (M), Valine (V); and    -   6) Phenylalanine (F), Tyrosine (Y), Tryptophan (W).

In some embodiments, the heavy chain of the antibody includes up to 10(such as up to 1, up to 2, up to 3, up to 4, up to 5, up to 6, up to 7,up to 8, or up to 9) amino acid substitutions (such as conservativeamino acid substitutions) compared to the amino acid sequence set forthas one of SEQ ID NOs: 1, 3, 5, or 7. In some embodiments, the lightchain of the antibody includes up to 10 (such as up to 1, up to 2, up to3, up to 4, up to 5, up to 6, up to 7, up to 8, or up to 9) amino acidsubstitutions (such as conservative amino acid substitutions) comparedto the amino acid sequence set forth as one of SEQ ID NOs: 2, 4, 6, or8.

In some embodiments, the antibody or antigen binding fragment caninclude up to 10 (such as up to 1, up to 2, up to 3, up to 4, up to 5,up to 6, up to 7, up to 8, or up to 9) amino acid substitutions (such asconservative amino acid substitutions) in the framework regions of theheavy chain of the antibody, or the light chain of the antibody, or theheavy and light chains of the antibody, compared to a known frameworkregion, or compared to the framework regions of the m825, m822, m830, orm863 antibodies as disclosed herein, and maintain the specific bindingactivity for TEM8 protein.

In certain embodiments, substitutions, insertions, or deletions mayoccur within one or more CDRs so long as such alterations do notsubstantially reduce the ability of the antibody to bind antigen. Forexample, conservative alterations (e.g., conservative substitutions asprovided herein) that do not substantially reduce binding affinity maybe made in CDRs. In certain embodiments of the variant VII and VLsequences provided above, each CDR either is unaltered, or contains nomore than one, two or three amino acid substitutions.

To increase binding affinity of the antibody, the V_(L) and V_(H)segments can be randomly mutated, such as within H-CDR3 region or theL-CDR3 region, in a process analogous to the in vivo somatic mutationprocess responsible for affinity maturation of antibodies during anatural immune response. Thus in vitro affinity maturation can beaccomplished by amplifying V_(H) and V_(L) regions using PCR primerscomplementary to the H-CDR3 or L-CDR3, respectively. In this process,the primers have been “spiked” with a random mixture of the fournucleotide bases at certain positions such that the resultant PCRproducts encode V_(H) and V_(L) segments into which random mutationshave been introduced into the V_(H) and/or V_(L) CDR3 regions. Theserandomly mutated V_(H) and V_(L) segments can be tested to determine thebinding affinity for TEM8 protein. In particular examples, the V_(H)amino acid sequence is one of SEQ ID NOs: 1, 3, 5, or 7. In otherexamples, the V_(L) amino acid sequence is SEQ ID NOs: 2, 4, 6, or 8.Methods of in vitro affinity maturation are known (see, e.g., Chowdhury,Methods Mol. Biol. 207:179-196 (2008)), and Hoogenboom et al. in Methodsin Molecular Biology 178:1-37 (O'Brien et al., ed., Human Press, Totowa,N.J., (2001).)

A useful method for identification of residues or regions of an antibodythat may be targeted for mutagenesis is called “alanine scanningmutagenesis” as described by Cunningham and Wells (1989) Science,244:1081-1085. In this method, a residue or group of target residues(e.g., charged residues such as arg, asp, his, lys, and glu) areidentified and replaced by a neutral or negatively charged amino acid(e.g., alanine or polyalanine) to determine whether the interaction ofthe antibody with antigen is affected. Further substitutions may beintroduced at the amino acid locations demonstrating functionalsensitivity to the initial substitutions. Alternatively, oradditionally, a crystal structure of an antigen-antibody complex is usedto identify contact points between the antibody and antigen. Suchcontact residues and neighboring residues may be targeted or eliminatedas candidates for substitution. Variants may be screened to determinewhether they contain the desired properties.

In certain embodiments, an antibody or antigen binding fragment isaltered to increase or decrease the extent to which the antibody orantigen binding fragment is glycosylated. Addition or deletion ofglycosylation sites may be conveniently accomplished by altering theamino acid sequence such that one or more glycosylation sites is createdor removed.

Where the antibody comprises an Fc region, the carbohydrate attachedthereto may be altered. Native antibodies produced by mammalian cellstypically comprise a branched, biantennary oligosaccharide that isgenerally attached by an N-linkage to Asn297 of the CH₂ domain of the Fcregion. See, e.g., Wright et al. TIBTECH 15:26-32 (1997). Theoligosaccharide may include various carbohydrates, e.g., mannose,N-acetyl glucosamine (GlcNAc), galactose, and sialic acid, as well as afucose attached to a GlcNAc in the “stem” of the biantennaryoligosaccharide structure. In some embodiments, modifications of theoligosaccharide in an antibody may be made in order to create antibodyvariants with certain improved properties.

In one embodiment, antibody variants are provided having a carbohydratestructure that lacks fucose attached (directly or indirectly) to an Fcregion. For example, the amount of fucose in such antibody may be from1% to 80%, from 1% to 65%, from 5% to 65% or from 20% to 40%. The amountof fucose is determined by calculating the average amount of fucosewithin the sugar chain at Asn297, relative to the sum of allglycostructures attached to Asn 297 (e.g. complex, hybrid and highmannose structures) as measured by MALDI-TOF mass spectrometry, asdescribed in WO 2008/077546, for example. Asn297 refers to theasparagine residue located at about position 297 in the Fc region;however, Asn297 may also be located about ±3 amino acids upstream ordownstream of position 297, i.e., between positions 294 and 300, due tominor sequence variations in antibodies. Such fucosylation variants mayhave improved ADCC function. See, e.g., US Patent Publication Nos. US2003/0157108 (Presta. L.); US 2004/0093621 (Kyowa Hakko Kogyo Co., Ltd).Examples of publications related to “defucosylated” or“fucose-deficient” antibody variants include: US 2003/0157108; WO2000/61739; WO 2001/29246; US 2003/0115614; US 2002/0164328; US2004/0093621; US 2004/0132140: US 2004/0110704; US 2004/0110282; US2004/0109865; WO 2003/085119; WO 2003/084570; WO 2005/035586; WO2005/035778; WO2005/053742; WO2002/031140; Okazaki et al. J. Mol. Biol.336:1239-1249 (2004); Yamane-Ohnuki et al. Biotech. Bioeng. 87: 614(2004). Examples of cell lines capable of producing defucosylatedantibodies include Lec 13 CHO cells deficient in protein fucosylation(Ripka et al. Arch. Biochem. Biophys. 249:533-545 (1986); US Pat Appl NoUS 2003/0157108 A1, Presta. L; and WO 2004/056312 A1, Adams et al.,especially at Example 11), and knockout cell lines, such asalpha-1,6-fucosyltransferase gene, FUT8, knockout CHO cells (see, e.g.,Yamane-Ohnuki et al. Biotech. Bioeng. 87: 614 (2004); Kanda. Y. et al.,Biotechnol. Bioeng., 94(4):680-688 (2006); and WO2003/085107).

Antibodies variants are further provided with bisected oligosaccharides,e.g., in which a biantennary oligosaccharide attached to the Fc regionof the antibody is bisected by GlcNAc. Such antibody variants may havereduced fucosylation and/or improved ADCC function. Examples of suchantibody variants are described, e.g., in WO 2003/011878 (Jean-Mairet etal.); U.S. Pat. No. 6,602,684 (Umana et al.); and US 2005/0123546 (Umanaet al.). Antibody variants with at least one galactose residue in theoligosaccharide attached to the Fc region are also provided. Suchantibody variants may have improved CDC function. Such antibody variantsare described, e.g., in WO 1997/30087 (Patel et al.); WO 1998/58964(Raju, S.): and WO 1999/22764 (Raju. S.).

In several embodiments, the constant region of the antibody includes oneor more amino acid substitutions to optimize in vivo half-life of theantibody. The serum half-life of IgG Abs is regulated by the neonatal Fcreceptor (FcRn). Thus, in several embodiments, the antibody includes anamino acid substitution that increases binding to the FcRn. Several suchsubstitutions are known to the person of ordinary skill in the art, suchas substitutions at IgG constant regions T250Q and M428L (see, e.g.,Hinton et al., J Immunol., 176:346-356, 2006); M428L and N434S (the “LS”mutation, see, e.g., Zalevsky, et al., Nature Biotechnology, 28:157-159,2010); N434A (see, e.g., Petkova et al., Int. Immunol., 18:1759-1769,2006); T307A, E380A, and N434A (see, e.g., Petkova et al., Int.Immunol., 18:1759-1769, 2006); and M252Y, S254T, and T256E (see, e.g.,Dall'Acqua et al., J. Biol. Chem., 281:23514-23524, 2006).

In some embodiments, the constant region of the antibody includes one ofmore amino acid substitutions to optimize Antibody-dependentcell-mediated cytotoxicity (ADCC). ADCC is mediated primarily through aset of closely related Fcγ receptors. In some embodiments, the antibodyincludes one or more amino acid substitutions that increase binding toFcγRIIIa. Several such substitutions are known to the person of ordinaryskill in the art, such as substitutions at IgG constant regions S239Dand 1332E (see, e.g., Lazar et al., Proc. Natl., Acad. Sci. U.S.A.,103:4005-4010, 2006); and S239D, A330L, and 1332E (see, e.g., Lazar etal., Proc. Natl., Acad. Sci. U.S.A., 103:4005-4010, 2006).

Combinations of the above substitutions are also included, to generatean IgG constant region with increased binding to FcRn and FcγRIIIa. Thecombinations increase antibody half-life and ADCC. For example, suchcombination include antibodies with the following amino acidsubstitution in the Fc region:

(1) S239D/I332E and T250Q/M428L;

(2) S239D/I332E and M4281L/N434S;

(3) S239D/I332E and N434A;

(4) S239D/I332E and T307A/E380A/N434A;

(5) S239D/I332E and M252Y/S254T/T256E;

(6) S239D/A330L/332E and T250Q/M428L;

(7) S239D/A330L/332E and M428L/N434S;

(8) S239D/A330L/332E and N434A;

(9) S239D/A330L/332E and T307A/E380A/N434A; or

(10) S239D/A330L/332E and M252Y/S254T/T256E.

In some examples, the antibodies, or an antigen binding fragment thereofis modified such that it is directly cytotoxic to infected cells, oruses natural defenses such as complement, antibody dependent cellularcytotoxicity (ADCC), or phagocytosis by macrophages.

In certain embodiments, an antibody provided herein may be furthermodified to contain additional nonproteinaceous moieties that are knownin the art and readily available. The moieties suitable forderivatization of the antibody include but are not limited to watersoluble polymers. Non-limiting examples of water soluble polymersinclude, but are not limited to, polyethylene glycol (PEG), copolymersof ethylene glycol/propylene glycol, carboxymethylcellulose, dextran,polyvinyl alcohol, polyvinyl pyrrolidone, poly-1,3-dioxolane,poly-1,3,6-trioxane, ethylene/maleic anhydride copolymer, polyaminoacids(either homopolymers or random copolymers), and dextran or poly(n-vinylpyrrolidone)polyethylene glycol, propropylene glycol homopolymers,prolypropylene oxide/ethylene oxide co-polymers, polyoxyethylatedpolyols (e.g., glycerol), polyvinyl alcohol, and mixtures thereof.Polyethylene glycol propionaldehyde may have advantages in manufacturingdue to its stability in water. The polymer may be of any molecularweight, and may be branched or unbranched. The number of polymersattached to the antibody may vary, and if more than one polymer areattached, they can be the same or different molecules. In general, thenumber and/or type of polymers used for derivatization can be determinedbased on considerations including, but not limited to, the particularproperties or functions of the antibody to be improved, whether theantibody derivative will be used in a therapy under defined conditions,etc.

The antibody or antigen binding fragment can be derivatized or linked toanother molecule (such as another peptide or protein). In general, theantibody or antigen binding fragment is derivatized such that thebinding to TEM8 is not affected adversely by the derivatization orlabeling. For example, the antibody or antigen binding fragment can befunctionally linked (by chemical coupling, genetic fusion, noncovalentassociation or otherwise) to one or more other molecular entities, suchas another antibody (for example, a bi-specific antibody or a diabody),a detectable marker, an effector molecule, or a protein or peptide thatcan mediate association of the antibody or antibody portion with anothermolecule (such as a streptavidin core region or a polyhistidine tag).

Also included are antibodies that bind to the same epitope on TEM8 towhich the TEM8 specific antibodies provided herein bind. Antibodies thatbind to such an epitope can be identified based on their ability tocross-compete (for example, to competitively inhibit the binding of, ina statistically significant manner) with the TEM8 specific antibodiesprovided herein in TEM8 binding assays (such as those described in theExamples). An antibody “competes” for binding when the competingantibody inhibits TEM8 binding of an antibody of the invention by morethan 50%, in the presence of competing antibody concentrations higherthan 10⁶×K_(D) of the competing antibody. In a certain embodiment, theantibody that binds to the same epitope on TEM8 as the antibodies of thepresent invention is a human monoclonal antibody. Such human monoclonalantibodies can be prepared and isolated as described herein.

B. Conjugates

Human monoclonal antibodies specific for TEM8, or antigen bindingfragments thereof, can be conjugated to an agent, such as an effectormolecule or detectable marker, using any number of means known to thoseof skill in the art. Both covalent and non-covalent attachment means maybe used. Conjugates include, but are not limited to, molecules in whichthere is a covalent linkage of an effector molecule or a detectablemarker to an antibody or antigen binding fragment that specificallybinds TEM8. One of skill in the art will appreciate that variouseffector molecules and detectable markers can be used, including (butnot limited to) chemotherapeutic agents, anti-angiogenic agents, toxins,radioactive agents such as ¹²⁵I, ³²P, ¹⁴C, ³H and ³⁵S and other labels,target moieties and ligands, etc.

The choice of a particular effector molecule or detectable markerdepends on the particular target molecule or cell, and the desiredbiological effect. Thus, for example, the effector molecule can be acytotoxin that is used to bring about the death of a particular targetcell (such as a tumor cell).

Effector molecules and detectable markers can be linked to an antibodyor antigen binding fragment of interest using any number of means knownto those of skill in the art. Both covalent and non-covalent attachmentmeans may be used. The procedure for attaching an effector molecule ordetectable marker to an antibody or antigen binding fragment variesaccording to the chemical structure of the effector. Polypeptidestypically contain a variety of functional groups; such as carboxylicacid (COOH), free amine (—NH₂) or sulfhydryl (—SH) groups, which areavailable for reaction with a suitable functional group on an antibodyto result in the binding of the effector molecule or detectable marker.Alternatively, the antibody or antigen binding fragment is derivatizedto expose or attach additional reactive functional groups. Thederivatization may involve attachment of any of a number of known linkermolecules such as those available from Pierce Chemical Company,Rockford, Ill. The linker can be any molecule used to join the antibodyor antigen binding fragment to the effector molecule or detectablemarker. The linker is capable of forming covalent bonds to both theantibody or antigen binding fragment and to the effector molecule ordetectable marker. Suitable linkers are well known to those of skill inthe art and include, but are not limited to, straight or branched-chaincarbon linkers, heterocyclic carbon linkers, or peptide linkers. Wherethe antibody or antigen binding fragment and the effector molecule ordetectable marker are polypeptides, the linkers may be joined to theconstituent amino acids through their side groups (such as through adisulfide linkage to cysteine) or to the alpha carbon amino and carboxylgroups of the terminal amino acids.

Additionally, in several embodiments, the linker can include a spacerelement, which, when present, increases the size of the linker such thatthe distance between the effector molecule or the detectable marker andthe antibody or antigen binding fragment is increased. Exemplary spacersare known to the person of ordinary skill, and include those listed inU.S. Pat. Nos. 7,964,566, 7,498,298, 6,884,869, 6,323,315, 6,239,104,6,034,065, 5,780,588, 5,665,860, 5,663,149, 5,635,483, 5,599,902,5,554,725, 5,530,097, 5,521,284, 5,504,191, 5,410,024, 5,138,036,5,076,973, 4,986,988, 4,978,744, 4,879,278, 4,816,444, and 4,486,414, aswell as U.S. Pat. Pub. Nos. 20110212088 and 20110070248, each of whichis incorporated by reference in its entirety.

Thus, in several embodiments, the conjugate includes a linker thatconnects the effector molecule or detectable marker to the TEM8-specificantibody or antigen binding fragment thereof. In some embodiments, thelinker is cleavable under intracellular conditions, such that cleavageof the linker releases the effector molecule or detectable marker fromthe antibody or antigen binding fragment in the intracellularenvironment. In yet other embodiments, the linker is not cleavable andthe effector molecule or detectable marker is released, for example, byantibody degradation. In some embodiments, the linker is cleavable by acleaving agent that is present in the intracellular environment (forexample, within a lysosome or endosome or caveolea). The linker can be,for example, a peptide linker that is cleaved by an intracellularpeptidase or protease enzyme, including, but not limited to, a lysosomalor endosomal protease. In some embodiments, the peptide linker is atleast two amino acids long or at least three amino acids long. However,the linker can be 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15 amino acidslong, such as 1-2, 1-3, 2-5, 3-10, 3-15, 1-5, 1-10, 1-15, amino acidslong. Proteases can include cathepsins B and D and plasmin, all of whichare known to hydrolyze dipeptide drug derivatives resulting in therelease of active drug inside target cells (see, for example, Dubowchikand Walker, 1999, Pharm. Therapeutics 83:67-123). For example, a peptidelinker that is cleavable by the thiol-dependent protease cathepsin-B,can be used (for example, a Phenylalanine-Leucine or aGlycine-Phenylalanine-Leucine-Glycine linker). Other examples of suchlinkers are described, for example, in U.S. Pat. No. 6,214,345,incorporated herein by reference. In a specific embodiment, the peptidelinker cleavable by an intracellular protease is a Valine-Citrulinelinker or a Phenylalanine-Lysine linker (see, for example, U.S. Pat. No.6,214,345, which describes the synthesis of doxorubicin with theValine-Citruline linker).

In other embodiments, the cleavable linker is pH-sensitive, i.e.,sensitive to hydrolysis at certain pH values. Typically, thepH-sensitive linker is hydrolyzable under acidic conditions. Forexample, an acid-labile linker that is hydrolyzable in the lysosome (forexample, a hydrazone, semicarbazone, thiosemicarbazone, cis-aconiticamide, orthoester, acetal, ketal, or the like) can be used. (See, forexample, U.S. Pat. Nos. 5,122,368; 5,824,805; 5,622,929; Dubowchik andWalker, 1999, Pharm. Therapeutics 83:67-123; Neville et al., 1989, Biol.Chem. 264:14653-14661.) Such linkers are relatively stable under neutralpH conditions, such as those in the blood, but are unstable at below pH5.5 or 5.0, the approximate pH of the lysosome. In certain embodiments,the hydrolyzable linker is a thioether linker (such as, for example, athioether attached to the therapeutic agent via an acylhydrazone bond(see, for example, U.S. Pat. No. 5,622,929).

In yet other embodiments, the linker is cleavable under reducingconditions (for example, a disulfide linker). A variety of disulfidelinkers are known in the art, including, for example, those that can beformed using SATA (N-succinimidyl-S-acetylthioacetate), SPDP(N-succinimidyl-3-(2-pyridyldithio)propionate), SPDB(N-succinimidyl-3-(2-pyridyldithio)butyrate) and SMPT(N-succinimidyl-oxycarbonyl-alpha-methyl-alpha-(2-pyridyl-dithio)toluene)-,SPDB and SMPT. (See, for example, Thorpe et al., 1987, Cancer Res.47:5924-5931; Wawrzynczak et al., In Immunoconjugates: AntibodyConjugates in Radioimagery and Therapy of Cancer (C. W. Vogel ed.,Oxford U. Press, 1987); Phillips et al., Cancer Res. 68:92809290, 2008).See also U.S. Pat. No. 4,880,935.)

In yet other specific embodiments, the linker is a malonate linker(Johnson et al., 1995, Anticancer Res. 15:1387-93), a maleimidobenzoyllinker (Lau et al., 1995, Bioorg-Med-Chem. 3(10):1299-1304), or a3′-N-amide analog (Lau et al., 1995, Bioorg-Med-Chem. 3(10):1305-12).

In yet other embodiments, the linker is not cleavable and the effectormolecule or detectable marker is released by antibody degradation. (SeeU.S. Publication No. 2005/0238649 incorporated by reference herein inits entirety).

In several embodiments, the linker is resistant to cleavage in anextracellular environment. For example, no more than about 20%, no morethan about 15%, no more than about 10%, no more than about 5%, no morethan about 3%, or no more than about 1% of the linkers, in a sample ofconjugate, are cleaved when the conjugate is present in an extracellularenvironment (for example, in plasma). Whether or not a linker isresistant to cleavage in an extracellular environment can be determined,for example, by incubating the conjugate containing the linker ofinterest with plasma for a predetermined time period (for example, 2, 4,8, 16, or 24 hours) and then quantitating the amount of free effectormolecule or detectable marker present in the plasma. A variety ofexemplary linkers that can be used in conjugates are described in WO2004-010957, U.S. Publication No. 2006/0074008, U.S. Publication No.20050238649, and U.S. Publication No. 2006/0024317, each of which isincorporated by reference herein in its entirety.

The antibodies or antigen binding fragments disclosed herein can bederivatized, for example, by cross-linking two or more antibodies (ofthe same type or of different types, such as to create bispecificantibodies). Suitable crosslinkers include those that areheterobifunctional, having two distinctly reactive groups separated byan appropriate spacer (such as m-maleimidobenzoyl-N-hydroxysuccinimideester) or homobifunctional (such as disuccinimidyl suberate). Suchlinkers are commercially available.

In view of the large number of methods that have been reported forattaching a variety of radiodiagnostic compounds, radiotherapeuticcompounds, labels (such as enzymes or fluorescent molecules), toxins,and other agents to antibodies one skilled in the art will be able todetermine a suitable method for attaching a given agent to an antibodyor antigen binding fragment or other polypeptide. For example, theantibody or antigen binding fragment can be conjugated with smallmolecular weight drugs such as Monomethyl Auristatin E (MMAE),Monomethyl Auristatin F (MMAF), maytansine, maytansine derivatives,including the derivative of maytansine known as DM1 (also known asmertansine), or other chemotherapeutic agents to make an antibody drugconjugate (ADC). In several embodiments, various chemotherapeutic agentsdescribed herein can be conjugated to the provided antibodies togenerate a conjugate.

In several embodiments, conjugates of an antibody or antigen bindingfragment and one or more small molecule toxins, such as a calicheamicin,maytansinoids, dolastatins, auristatins, a trichothecene, and CC1065,and the derivatives of these toxins that have toxin activity, areprovided.

Maytansine compounds suitable for use as maytansinoid toxin moieties arewell known in the art, and can be isolated from natural sourcesaccording to known methods, produced using genetic engineeringtechniques (see Yu et al (2002) PNAS 99:7968-7973), or maytansinol andmaytansinol analogues prepared synthetically according to known methods.Maytansinoids are mitototic inhibitors which act by inhibiting tubulinpolymerization. Maytansine was first isolated from the east Africanshrub Maytenus serrata (U.S. Pat. No. 3,896,111). Subsequently, it wasdiscovered that certain microbes also produce maytansinoids, such asmaytansinol and C-3 maytansinol esters (U.S. Pat. No. 4,151,042).Synthetic maytansinol and derivatives and analogues thereof aredisclosed, for example, in U.S. Pat. Nos. 4,137,230; 4,248,870;4,256,746; 4,260,608; 4,265,814; 4,294,757; 4,307,016; 4,308,268;4,308,269; 4,309,428; 4,313,946; 4,315,929; 4,317,821; 4,322,348;4,331,598; 4,361,650; 4,364,866; 4,424,219; 4,450,254; 4,362,663; and4,371,533, each of which is incorporated herein by reference. Conjugatescontaining maytansinoids, methods of making same, and their therapeuticuse are disclosed, for example, in U.S. Pat. Nos. 5,208,020; 5,416,064;6,441,163 and European Patent EP 0 425 235 B1, the disclosures of whichare hereby expressly incorporated by reference.

In one example, the conjugate includes a monoclonal antibody thatspecifically binds TEM8 (or antigen binding fragment thereof), anon-reducible thioester linker and the maytansinoid toxin DM1; forexample the conjugate can include the structure set forth as (wherein“mAb” refers to the monoclonal antibody or antigen binding fragmentthereof):

In some embodiments, the effector molecule is an auristatin, such asauristatin E (also known in the art as a derivative of dolastatin-10) ora derivative thereof. The auristatin can be, for example, an esterformed between auristatin E and a keto acid. For example, auristatin Ecan be reacted with paraacetyl benzoic acid or benzoylvaleric acid toproduce AEB and AEVB, respectively. Other exemplary auristatins includeAFP, MMAF, and MMAE. The synthesis and structure of exemplaryauristatins are described in U.S. Patent Application Publication No.2003/0083263; International Patent Publication No. WO 04/010957,International Patent Publication No. WO 02/088172, and U.S. Pat. Nos.7,498,298, 6,884,869, 6,323,315; 6,239,104; 6,034,065; 5,780,588;5,665,860; 5,663,149; 5,635,483; 5,599,902; 5,554,725; 5,530,097;5,521,284; 5,504,191; 5,410,024; 5,138,036; 5,076,973; 4,986,988;4,978,744; 4,879,278; 4,816,444; and 4,486,414, each of which isincorporated by reference herein in its entirety. Additional descriptionof antibody drug conjugates including the auristatin MMAE, and methodsof making such conjugates, is provided in, e.g., U.S. Pub. Nos.2011/0268751, 2008/0305044, 2007/0258987, each of which is incorporatedby reference herein in its entirety). Auristatins have been shown tointerfere with microtubule dynamics and nuclear and cellular divisionand have anticancer activity. Auristatins bind tubulin and can exert acytotoxic or cytostatic effect on cells. There are a number of differentassays, known in the art, which can be used for determining whether anauristatin or resultant conjugate exerts a cytostatic or cytotoxiceffect on a desired cell line.

In one example, the conjugate includes a monoclonal antibody thatspecifically binds TEM8 (or antigen binding fragment thereof), acleavable linker including a Valine-Citruline (Val-Cit) peptide cleavagesite, a spacer, and the toxin MMAE; for example the conjugate caninclude the structure set forth as (wherein “mAb” refers to themonoclonal antibody or antigen binding fragment thereof):

In one preferred embodiment, the conjugate may be

where n is an integer (such as an even integer) from 0 to 10 (such as 0to 8, 0 to 4, 2 to 4, 2 to 8, 1 to 10, 1 to 8, or 1 to 4, or 2, 4, 6, or8), A is a monoclonal antibody or antigen binding fragment thereofcomprising a heavy chain variable region comprising a heavy chaincomplementarity determining region (H-CDR)1, a H-CDR2, and a H-CDR3comprising amino acids 26-33, 51-58, and 97-106 of SEQ ID NO: 1,respectively, and a light chain variable region comprising a light chaincomplementarity determining region (L-CDR)1, a L-CDR2, and a L-CDR3comprising amino acids 26-31, 49-51, and 88-97 of SEQ ID NO: 2,respectively, wherein the antibody or antigen binding fragmentspecifically binds to TEM8, and S is a sulfur atom from the antibody. Inone embodiment, preferably n is an even integer from 0 to 8, preferablyfrom 0 to 4. The S moiety can be exposed by reduction or partialreduction of the inter-chain disulfides of the antibody (e.g., bytreatment with a reducing agent such as DTT or TCEP).

In one non-limiting embodiment, the conjugate may be

where n is 4, and A is a monoclonal antibody or antigen binding fragmentthereof comprising a heavy chain variable region comprising a heavychain complementarity determining region (H-CDR)1, a H-CDR2, and aH-CDR3 comprising amino acids 26-33, 51-58, and 97-106 of SEQ ID NO: 1,respectively, and a light chain variable region comprising a light chaincomplementarity determining region (L-CDR)1, a L-CDR2, and a L-CDR3comprising amino acids 26-31, 49-51, and 88-97 of SEQ ID NO: 2,respectively, wherein the antibody or antigen binding fragmentspecifically binds to TEM8. In some such embodiments, the heavy chainvariable region comprises the amino acid sequence set forth as SEQ IDNO: 1 and the light chain variable region comprises the amino acidsequence set forth as SEQ ID NO: 2, and S is a sulfur atom from theantibody or antigen binding fragment thereof.

Additional toxins can be employed with antibodies that specifically bindTEM8, and antigen binding fragment of these antibodies. Exemplary toxinsinclude Pseudomonas exotoxin (PE), ricin, abrin, diphtheria toxin andsubunits thereof, ribotoxin, ribonuclease, saporin, and calicheamicin,as well as botulinum toxins A through F. These toxins are well known inthe art and many are readily available from commercial sources (forexample, Sigma Chemical Company, St. Louis, Mo.). Contemplated toxinsalso include variants of the toxins (see, for example, see, U.S. Pat.Nos. 5,079,163 and 4,689,401). In some embodiments, these conjugates areof use for the treatment of a carcinoma, for example a breast carcinoma,colorectal carcinoma, lung carcinoma and melanoma.

Saporin is a toxin derived from Saponaria officinalis that disruptsprotein synthesis by inactivating the 60S portion of the ribosomalcomplex (Stirpe et al., Bio/Technology, 10:405-412, 1992). However, thetoxin has no mechanism for specific entry into cells, and thereforerequires conjugation to an antibody or antigen binding fragment thatrecognizes a cell-surface protein that is internalized in order to beefficiently taken up by cells.

Diphtheria toxin is isolated from Corynebacterium diphtheriae.Typically, diphtheria toxin for use in immunotoxins is mutated to reduceor to eliminate non-specific toxicity. A mutant known as CRM107, whichhas full enzymatic activity but markedly reduced non-specific toxicity,has been known since the 1970's (Laird and Groman, J. Virol. 19:220,1976), and has been used in human clinical trials. See, U.S. Pat. No.5,792,458 and U.S. Pat. No. 5,208,021.

Ricin is the lectin RCA60 from Ricinus communis (Castor bean). Forexamples of ricin, see, U.S. Pat. No. 5,079,163 and U.S. Pat. No.4,689,401. Ricinus communis agglutinin (RCA) occurs in two formsdesignated RCA₆₀ and RCA₁₂₀ according to their molecular weights ofapproximately 65 and 120 kD, respectively (Nicholson & Blaustein, J.Biochim. Biophys. Acta 266:543, 1972). The A chain is responsible forinactivating protein synthesis and killing cells. The B chain bindsricin to cell-surface galactose residues and facilitates transport ofthe A chain into the cytosol (Olsnes et al., Nature 249:627-631, 1974and U.S. Pat. No. 3,060,165).

Ribonucleases have also been conjugated to targeting molecules for useas immunotoxins (see Suzuki et al., Nat. Biotech. 17:265-70, 1999).Exemplary ribotoxins such as α-sarcin and restrictocin are discussed in,for example Rathore et al., Gene 190:31-5, 1997; and Goyal and Batra,Biochem. 345 Pt 2:247-54, 2000. Calicheamicins were first isolated fromMicromonospora echinospora and are members of the enediyne antitumorantibiotic family that cause double strand breaks in DNA that lead toapoptosis (see, for example Lee et al., J. Antibiot. 42:1070-87, 1989).The drug is the toxic moiety of an immunotoxin in clinical trials (see,for example, Gillespie et al., Ann. Oncol. 11:735-41, 2000).

Abrin includes toxic lectins from Abrus precatorius. The toxicprinciples, abrin a, b, c, and d, have a molecular weight of from about63 and 67 kD and are composed of two disulfide-linked polypeptide chainsA and B. The A chain inhibits protein synthesis; the B chain (abrin-b)binds to D-galactose residues (see, Funatsu et al., Agr. Biol. Chem.52:1095, 1988; and Olsnes, Methods Enzymol. 50:330-335, 1978).

In one embodiment, the toxin is Pseudomonas exotoxin (PE) (U.S. Pat. No.5,602,095). As used herein, PE includes full-length native (naturallyoccurring) PE or a PE that has been modified. Such modifications caninclude, but are not limited to, elimination of domain Ia, various aminoacid deletions in domains Ib, II and III, single amino acidsubstitutions and the addition of one or more sequences at the carboxylterminus (for example, see Siegall et al., J. Biol. Chem.264:14256-14261, 1989). PE employed with the provided antibodies caninclude the native sequence, cytotoxic fragments of the native sequence,and conservatively modified variants of native PE and its cytotoxicfragments. Cytotoxic fragments of PE include those which are cytotoxicwith or without subsequent proteolytic or other processing in the targetcell. Cytotoxic fragments of PE include PE40, PE38, and PE35. Foradditional description of PE and variants thereof, see for example, U.S.Pat. Nos. 4,892,827; 5,512,658; 5,602,095; 5,608,039; 5,821,238; and5,854,044; PCT Publication No. WO 99/51643; Pai et al., Proc. Natl.Acad. Sci. USA, 88:3358-3362, 1991; Kondo et al., J. Biol. Chem.,263:9470-9475, 1988; Pastan et al., Biochim. Biophys. Acta, 1333:C1-C6,1997.

Also contemplated herein are protease-resistant PE variants and PEvariants with reduced immunogenicity, such as, but not limited to PE-LR,PE-6X, PE-8X, PE-LR/6X and PE-LR/8X (see, for example, Weldon et al.,Blood 113(16):3792-3800, 2009; Onda et al., Proc. Natl. Acad. Sci. USA,105(32):11311-11316, 2008; and PCT Publication Nos. WO 2007/016150, WO2009/032954 and WO 2011/032022, which are herein incorporated byreference).

In some examples, the PE is a variant that is resistant to lysosomaldegradation, such as PE-LR (Weldon et al., Blood 113(16):3792-3800,2009; PCT Publication No. WO 2009/032954). In other examples, the PE isa variant designated PE-LR/6X (PCT Publication No. WO 2011/032022). Inother examples, the PE is a variant designated PE-LR/8M (PCT PublicationNo. WO 2011/032022).

A monoclonal antibody that specifically binds TEM8 (or antigen bindingfragment thereof) can also be conjugated with a detectable marker; forexample, a detectable marker capable of detection by ELISA,spectrophotometry, flow cytometry, microscopy or diagnostic imagingtechniques (such as computed tomography (CT), computed axial tomography(CAT) scans, magnetic resonance imaging (MRI), nuclear magneticresonance imaging NMRI), magnetic resonance tomography (MTR),ultrasound, fiberoptic examination, and laparoscopic examination).Specific, non-limiting examples of detectable markers includefluorophores, chemiluminescent agents, enzymatic linkages, radioactiveisotopes and heavy metals or compounds (for example super paramagneticiron oxide nanocrystals for detection by MRI). For example, usefuldetectable markers include fluorescent compounds, including fluorescein,fluorescein isothiocyanate, rhodamine,5-dimethylamine-1-napthalenesulfonyl chloride, phycoerythrin, lanthanidephosphors and the like. Bioluminescent markers are also of use, such asluciferase, Green fluorescent protein (GFP), Yellow fluorescent protein(YFP). An antibody or antigen binding fragment can also be conjugatedwith enzymes that are useful for detection, such as horseradishperoxidase, β-galactosidase, luciferase, alkaline phosphatase, glucoseoxidase and the like. When an antibody or antigen binding fragment isconjugated with a detectable enzyme, it can be detected by addingadditional reagents that the enzyme uses to produce a reaction productthat can be discerned. For example, when the agent horseradishperoxidase is present the addition of hydrogen peroxide anddiaminobenzidine leads to a colored reaction product, which is visuallydetectable. An antibody or antigen binding fragment may also beconjugated with biotin, and detected through indirect measurement ofavidin or streptavidin binding. It should be noted that the avidinitself can be conjugated with an enzyme or a fluorescent label.

An antibody or antigen binding fragment may be conjugated with aparamagnetic agent, such as gadolinium. Paramagnetic agents such assuperparamagnetic iron oxide are also of use as labels. Antibodies canalso be conjugated with lanthanides (such as europium and dysprosium),and manganese. An antibody or antigen binding fragment may also belabeled with a predetermined polypeptide epitopes recognized by asecondary reporter (such as leucine zipper pair sequences, binding sitesfor secondary antibodies, metal binding domains, epitope tags).

An antibody or antigen binding fragment can also be conjugated with aradiolabeled amino acid. The radiolabel may be used for both diagnosticand therapeutic purposes. For instance, the radiolabel may be used todetect TEM8 and TEM8 expressing cells by x-ray, emission spectra, orother diagnostic techniques. Further, the radiolabel may be usedtherapeutically as a toxin for treatment of tumors in a subject, forexample for treatment of breast carcinoma, lung carcinoma, colorectalcarcinoma or melanoma. Examples of labels for polypeptides include, butare not limited to, the following radioisotopes or radionucleotides: ³H,¹⁴C, ¹⁵N, ³⁵S, ⁹⁰Y, ⁹⁹Tc, ¹¹¹In, ¹²⁵I, ¹³¹I.

Means of detecting such detectable markers are well known to those ofskill in the art. Thus, for example, radiolabels may be detected usingphotographic film or scintillation counters, fluorescent markers may bedetected using a photodetector to detect emitted illumination. Enzymaticlabels are typically detected by providing the enzyme with a substrateand detecting the reaction product produced by the action of the enzymeon the substrate, and colorimetric labels are detected by simplyvisualizing the colored label.

An antibody or antigen binding fragment can also be derivatized with achemical group such as polyethylene glycol (PEG), a methyl or ethylgroup, or a carbohydrate group. These groups may be useful to improvethe biological characteristics of the antibody or antigen bindingfragment, such as to increase serum half-life or to increase tissuebinding.

The average number of effector molecule or detectable marker moietiesper antibody or antigen binding fragment in a conjugate can range, forexample, from 1 to 20 moieties per antibody or antigen binding fragment.For some conjugates, the average number of effector molecule ordetectable marker moieties per antibody or antigen binding fragment maybe limited by the number of attachment sites on the antibody or antigenbinding fragment. For example, where the attachment is a cysteine thiol,an antibody or antigen binding fragment may have only one or severalcysteine thiol groups, or may have only one or several sufficientlyreactive thiol groups through which a linker may be attached. In certainembodiments, the average number of effector molecule or detectablemarker moieties per antibody or antigen binding fragment in a conjugaterange from 1 to about 8; from about 2 to about 6; from about 3 to about5; from about 3 to about 4; from about 3.1 to about 3.9; from about 3.2to about 3.8; from about 3.2 to about 3.7; from about 3.2 to about 3.6;from about 3.3 to about 3.8; or from about 3.3 to about 3.7. See, forexample, U.S. Pat. No. 7,498,298, incorporated by reference herein inits entirety. The average number of effector molecule or detectablemarker moieties per antibody or antigen binding fragment in preparationsof conjugates may be characterized by conventional means such as massspectroscopy and, ELISA assay. The loading (for example, effectormolecule/antibody ratio) of an conjugate may be controlled in differentways, for example, by: (i) limiting the molar excess of effectormolecule-linker intermediate or linker reagent relative to antibody,(ii) limiting the conjugation reaction time or temperature, (iii)partial or limiting reductive conditions for cysteine thiolmodification, (iv) engineering by recombinant techniques the amino acidsequence of the antibody such that the number and position of cysteineresidues is modified for control of the number or position oflinker-effector molecule attachments (such as thioMab or thioFabprepared as disclosed in WO2006/03448, incorporated by reference hereinin its entirety.

C. Chimeric Antigen Receptors (CARs)

Also disclosed herein are chimeric antigen receptor (CARs) that areartificially constructed chimeric proteins including an extracellularantigen binding domain (e.g., single chain variable fragment (scFv))that specifically binds to TEM8, linked to a transmembrane domain,linked to one or more intracellular T-cell signaling domains.Characteristics of the disclosed CARs include their ability to redirectT-cell specificity and reactivity towards TEM8 expressing cells in anon-MHC-restricted manner. The non-MHC-restricted TEM8 recognition givesT cells expressing a disclosed CAR the ability to recognize antigenindependent of antigen processing.

The intracellular T cell signaling domains can include, for example, a Tcell receptor signaling domain, a T cell costimulatory signaling domain,or both. The T cell receptor signaling domain refers to a portion of theCAR comprising the intracellular domain of a T cell receptor, such asthe intracellular portion of the CD3 zeta protein. The costimulatorysignaling domain refers to a portion of the CAR comprising theintracellular domain of a costimulatory molecule, which is a cellsurface molecule other than an antigen receptor or their ligands thatare required for an efficient response of lymphocytes to antigen.

1. Extracellular Region

Several embodiments provide a CAR including an antigen binding domainthat specifically binds to TEM8 as disclosed herein. For example, theantigen binding domain can be a scFv including the heavy chain variableregion and the light chain variable region of any of the antibodies orantigen binding fragments thereof disclosed above.

In some embodiment, the antigen binding domain can include a heavy chainvariable region and a light chain variable region including the HCDR1,HCDR2, and HCDR3, and LCDR1, LCDR2, and LCDR3 of the of the heavy andlight chain variable regions, respectively, of one of the m825, m822.M830, or m863 antibodies (e.g., as set forth in Table 1 or Table 2).

In some embodiments, the antigen binding domain includes a heavy chainvariable region and a light chain variable region including the aminoacid sequences set forth as SEQ ID NOs: 1 and 2, respectively; SEQ IDNOs: 3 and 4, respectively; SEQ ID NOs: 5 and 6, respectively; or SEQ IDNOs: 7 and 8, respectively.

In several embodiments, the antigen binding domain can be a scFv. Insome embodiments, the scFv includes a heavy chain variable region and alight chain variable region joined by a peptide linker, such as a linkerincluding the amino acid sequence set forth as GGGGSGGGGSGGGGS (SEQ IDNO: 19).

The CAR can include a signal peptide sequence, e.g., N-terminal to theantigen binding domain. The signal peptide sequence may comprise anysuitable signal peptide sequence. In an embodiment, the signal peptidesequence is a human granulocyte-macrophage colony-stimulating factor(GM-CSF) receptor sequence, such as an amino acid sequence including orconsisting of LLVTSLLLCELPHPAFLLIPDT SEQ ID NO: 20. While the signalpeptide sequence may facilitate expression of the CAR on the surface ofthe cell, the presence of the signal peptide sequence in an expressedCAR is not necessary in order for the CAR to function. Upon expressionof the CAR on the cell surface, the signal peptide sequence may becleaved off of the CAR. Accordingly, in some embodiments, the CAR lacksa signal peptide sequence.

Between the antigen binding domain and the transmembrane domain of theCAR, there may be a spacer domain, which includes a polypeptidesequence. The spacer domain may comprise up to 300 amino acids,preferably 10 to 100 amino acids and most preferably 25 to 50 aminoacids. In some embodiments, the spacer domain can include animmunoglobulin domain, such as a human immunoglobulin sequence. In anembodiment, the immunoglobulin domain comprises an immunoglobulin CH2and CH3 immunoglobulin G (IgG1) domain sequence (CH2CH3). In thisregard, the spacer domain can include an immunoglobulin domaincomprising or consisting of the amino acid sequence set forth as SEQ IDNO: 21:

EPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGKKDPK

Without being bound to a particular theory, it is believed that theCH2CH3 domain extends the antigen binding domain of the CAR away fromthe membrane of CAR-expressing cells and may more accurately mimic thesize and domain structure of a native TCR.

2. Transmembrane Domain

With respect to the transmembrane domain, the CAR can be designed tocomprise a transmembrane domain that is fused to the extracellulardomain of the CAR. In one embodiment, the transmembrane domain thatnaturally is associated with one of the domains in the CAR is used.

The transmembrane domain may be derived either from a natural or from asynthetic source. Where the source is natural, the domain may be derivedfrom any membrane-bound or transmembrane protein. Exemplarytransmembrane domains for use in the disclosed CARs can include at leastthe transmembrane region(s) of) the alpha, beta or zeta chain of theT-cell receptor, CD28, CD3 epsilon, CD45, CD4, CD5, CDS, CD9, CD 16,CD22, CD33, CD37, CD64, CD80, CD86, CD 134, CD137, CD154. Alternativelythe transmembrane domain may be synthetic, in which case it willcomprise predominantly hydrophobic residues such as leucine and valine.In several embodiments, a triplet of phenylalanine, tryptophan andvaline will be found at each end of a synthetic transmembrane domain.

Optionally, a short oligo- or polypeptide linker, preferably between 2and 10 amino acids in length may form the linkage between thetransmembrane domain and the intracellular T cell signaling domainand/or T cell costimulatory domain of the CAR. A exemplary linkersequence includes one or more glycine-serine doublets.

In some embodiments, the transmembrane domain comprises thetransmembrane domain of a T cell receptor, such as a CD8 transmembranedomain. Thus, the CAR can include a CD8 transmembrane domain includingor consisting of SEQ ID NO: 22:

TTTPAPRPPTPAPTIASQPLSLRPEACRPAAGGAVHTRGLDFACDIYIWAP LAGTCGVLLLSLVITLYCIn another embodiment, the transmembrane domain comprises thetransmembrane domain of a T cell costimulatory molecule, such as CD137or CD28. Thus, the CAR can include a CD28 transmembrane domain includingor consisting of SEQ ID NO: 23:

IEVMYPPPYLDNEKSNGTIIHVKGKHLCPSPLFPGPSKPFWVLVVVGGVLA CYSLLVTVAFIIFWVR3. Intracellular Region

The intracellular region of the CAR includes one or more intracellular Tcell signaling domains responsible for activation of at least one of thenormal effector functions of a T cell in which the CAR is expressed orplaced in. Exemplary T cell signaling domains are provided herein, andare known to the person of ordinary skill in the art.

While an entire intracellular T cell signaling domain can be employed ina CAR, in many cases it is not necessary to use the entire chain. To theextent that a truncated portion of the intracellular T cell signalingdomain is used, such truncated portion may be used in place of theintact chain as long as it transduces the relevant T cell effectorfunction signal.

Examples of intracellular T cell signaling domains for use in the CARinclude the cytoplasmic sequences of the T cell receptor (TCR) andco-stimulatory molecules that act in concert to initiate signaltransduction following antigen receptor engagement, as well as anyderivative or variant of these sequences and any synthetic sequence thathas the same functional capability.

T cell receptor signaling domains regulate primary activation of the Tcell receptor complex either in a stimulatory way, or in an inhibitoryway. The disclosed CARs can include primary cytoplasmic signalingsequences that act in a stimulatory manner, which may contain signalingmotifs that are known as immunoreceptor tyrosine-based activation motifsor ITAMs. Examples of ITAM containing primary cytoplasmic signalingsequences that can be included in a disclosed CAR include include thosefrom CD3 zeta, FcR gamma, FcR beta, CD3 gamma, CD3 delta, CD3 epsilon,CDS, CD22, CD79a, CD79b, and CD66d proteins. In several embodiments, thecytoplasmic signaling molecule in the CAR includes an intracellular Tcell signaling domain from CD3 zeta.

The intracellular region of the CAR can include the ITAM containingprimary cytoplasmic signaling domain (such as CD3-zeta) by itself orcombined with any other desired cytoplasmic domain(s) useful in thecontext of a CAR. For example, the cytoplasmic domain of the CAR caninclude a CD3 zeta chain portion and an intracellular costimulatorysignaling domain. The costimulatory signaling domain refers to a portionof the CAR comprising the intracellular domain of a costimulatorymolecule. A costimulatory molecule is a cell surface molecule other thanan antigen receptor or their ligands that is required for an efficientresponse of lymphocytes to an antigen. Examples of such moleculesinclude CD27, CD28, 4-1BB (CD137), OX40 (CD134), CD30, CD40, PD-1, ICOS,lymphocyte function-associated antigen 1 (LFA-1), CD2, CD7, LIGHT,NKG2C, and B7-H3. An additional example of a signaling domain that canbe included in a disclosed CARs is a Tumor necrosis factor receptorsuperfamily member 18 (TNFRSF18; also known as glucocorticoid-inducedTNFR-related protein, GITR) signaling domain.

In some embodiments, the CAR can include a CD3 zeta signaling domain, aCD8 signaling domain, a CD28 signaling domain, a CD137 signaling domainor a combination of two or more thereof. In one embodiment, thecytoplasmic domain includes the signaling domain of CD3-zeta and thesignaling domain of CD28. In another embodiment, the cytoplasmic domainincludes the signaling domain of CD3 zeta and the signaling domain ofCD137. In yet another embodiment, the cytoplasmic domain includes thesignaling domain of CD3-zeta and the signaling domain of CD28 and CD137.The order of the one or more T cell signaling domains on the CAR can bevaried as needed by the person of ordinary skill in the art.

Exemplary amino acid sequences for such T cell signaling domains areprovided. For example, the CD3 zeta signaling domain can include orconsist of the amino acid sequence set forth as SEQ ID NO: 24(RVKFSRSADAPAYQQGQNQLYNELNLGRREEYDVLDKRRGRDPEMGGKPRRKNPQEGLYNELQKDKMAEAYSEIGMKGERRRGKGHDGLYQGLSTATKDTYDALHMQALPPR), the CD8 signalingdomain can include or consist of the amino acid sequence set forth asSEQ ID NO: 25(FVPVFLPAKPITTPAPRPPTPAPTIASQPLSLRPEACRPAAGGAVHTRGLDFACDIYIWAPLAGTCGVLLLSLVITLYCNHRNR), the CD28 signaling domain can include or consist ofthe amino acid sequence set forth as SEQ ID NO: 26(SKRSRLLHSDYMNMTPRRPGPTRKHYQPYAPPRDFAAYRS), the CD137 signaling domaincan include or consist of the amino acid sequences set forth as SEQ IDNO: 27 (KRGRKKLLYIFKQPFMRPVQTTQEEDGCSCRFPEEEEGGCEL) or SEQ ID NO: 28(RFSVVKRGRKKLLYIFKQPFMRPVQTTQEEDGCSCRFPEEEEGGCEL).

The cytoplasmic signaling sequences within the cytoplasmic signalingportion of the CAR of the invention may be linked to each other in arandom or specified order. Optionally, a short polypeptide linker,preferably between 2 and 10 amino acids in length may form the linkage.A glycine-serine doublet provides a particularly suitable linker.Further, between the signaling domain and the transmembrane domain ofthe CAR, there may be a spacer domain, which includes a polypeptidesequence. The spacer domain may comprise up to 300 amino acids,preferably 10 to 100 amino acids and most preferably 25 to 50 aminoacids.

4. Additional Description of CARs

Also provided are functional portions of the CARs described herein. Theterm “functional portion” when used in reference to a CAR refers to anypart or fragment of the CAR, which part or fragment retains thebiological activity of the CAR of which it is a part (the parent CAR).Functional portions encompass, for example, those parts of a CAR thatretain the ability to recognize target cells, or detect, treat, orprevent a disease, to a similar extent, the same extent, or to a higherextent, as the parent CAR. In reference to the parent CAR, thefunctional portion can comprise, for instance, about 10%, 25%, 30%, 50%,68%, 80%, 90%, 95%, or more, of the parent CAR.

The CAR or functional portion thereof, can include additional aminoacids at the amino or carboxy terminus, or at both termini, whichadditional amino acids are not found in the amino acid sequence of theparent CAR. Desirably, the additional amino acids do not interfere withthe biological function of the CAR or functional portion, e.g.,recognize target cells, detect cancer, treat or prevent cancer, etc.More desirably, the additional amino acids enhance the biologicalactivity, as compared to the biological activity of the parent CAR.

Also provided are functional variants of the CARs described herein,which have substantial or significant sequence identity or similarity toa parent CAR, which functional variant retains the biological activityof the CAR of which it is a variant. Functional variants encompass, forexample, those variants of the CAR described herein (the parent CAR)that retain the ability to recognize target cells to a similar extent,the same extent, or to a higher extent, as the parent CAR. In referenceto the parent CAR, the functional variant can, for instance, be at leastabout 30%, about 50%, about 75%, about 80%, about 85%, about 90%, about91%, about 92%, about 93%, about 94%, about 95%, about 96%), about 97%,about 98%, about 99% or more identical in amino acid sequence to theparent CAR.

A functional variant can, for example, comprise the amino acid sequenceof the parent CAR with at least one conservative amino acidsubstitution. Alternatively or additionally, the functional variants cancomprise the amino acid sequence of the parent CAR with at least onenon-conservative amino acid substitution. In this case, it is preferablefor the non-conservative amino acid substitution to not interfere withor inhibit the biological activity of the functional variant. Thenon-conservative amino acid substitution may enhance the biologicalactivity of the functional variant, such that the biological activity ofthe functional variant is increased as compared to the parent CAR.

The CARs (including functional portions and functional variants) can beof any length, i.e., can comprise any number of amino acids, providedthat the CARs (or functional portions or functional variants thereof)retain their biological activity, e.g., the ability to specifically bindto antigen, detect diseased cells in a mammal, or treat or preventdisease in a mammal, etc. For example, the CAR can be about 50 to about5000 amino acids long, such as 50, 70, 75, 100, 125, 150, 175, 200, 300,400, 500, 600, 700, 800, 900, 1000 or more amino acids in length.

The CARs (including functional portions and functional variants of theinvention) can comprise synthetic amino acids in place of one or morenaturally-occurring amino acids. Such synthetic amino acids are known inthe art, and include, for example, aminocyclohexane carboxylic acid,norleucine, α-amino n-decanoic acid, homoserine,S-acetylaminomethyl-cysteine, trans-3- and trans-4-hydroxyproline,4-aminophenylalanine, 4-nitrophenylalanine, 4-chlorophenylalanine,4-carboxyphenylalanine, β-phenylserine β-hydroxyphenylalanine,phenylglycine, α-naphthylalanine, cyclohexylalanine, cyclohexylglycine,indoline-2-carboxylic acid, 1,2,3,4-tetrahydroisoquinoline-3-carboxylicacid, aminomalonic acid, aminomalonic acid monoamide,N′-benzyl-N′-methyl-lysine, N′,N′-dibenzyl-lysine, 6-hydroxylysine,ornithine, α-aminocyclopentane carboxylic acid, α-aminocyclohexanecarboxylic acid, oc-aminocycloheptane carboxylic acid,-(2-amino-2-norbornane)-carboxylic acid, γ-diaminobutyric acid,α,β-diaminopropionic acid, homophenylalanine, and α-tert-butylglycine.

The CARs (including functional portions and functional variants) can beglycosylated, amidated, carboxylated, phosphorylated, esterified,N-acylated, cyclized via, e.g., a disulfide bridge, or converted into anacid addition salt and/or optionally dimerized or polymerized, orconjugated.

Methods of generating chimeric antigen receptors, T cells including suchreceptors, and their use (e.g., for treatment of cancer) are known inthe art and further described herein (see, e.g., Brentjens et al., 2010,Molecular Therapy, 18:4, 666-668; Morgan et al., 2010, MolecularTherapy, published online Feb. 23, 2010, pages 1-9; Till et al., 2008,Blood, 1 12:2261-2271; Park et al., Trends Biotechnol., 29:550-557,2011; Grupp et al., N Engl J Med., 368:1509-1518, 2013; Han et al., J.Hematol Oncol., 6:47, 2013; PCT Pub. WO2012/079000, WO2013/126726; andU.S. Pub. 2012/0213783, each of which is incorporated by referenceherein in its entirety.) For example, a nucleic acid molecule encoding adisclosed chimeric antigen binding receptor can be included in anexpression vector (such as a lentiviral vector) for expression in a hostcell, such as a T cell, to make the disclosed CAR. In some embodiments,methods of using the chimeric antigen receptor include isolating T cellsfrom a subject, transforming the T cells with an expression vector (suchas a lentiviral vector) encoding the chimeric antigen receptor, andadministering the engineered T cells expressing the chimeric antigenreceptor to the subject for treatment, for example for treatment of atumor in the subject.

D. Polynucleotides and Expression

Nucleic acids encoding the amino acid sequences of antibodies, antibodybinding fragments, conjugates, and CARs that specifically bind TEM8 areprovided. Nucleic acids encoding these molecules can readily be producedby one of skill in the art, using the amino acid sequences providedherein (such as the CDR sequences, heavy chain and light chainsequences), sequences available in the art (such as frameworksequences), and the genetic code. One of skill in the art can readilyuse the genetic code to construct a variety of functionally equivalentnucleic acids, such as nucleic acids which differ in sequence but whichencode the same antibody sequence, or encode a conjugate or fusionprotein including the V_(L) and/or V_(H) nucleic acid sequence.

Nucleic acid sequences encoding the of antibodies, antibody bindingfragments, conjugates, and CARs that specifically bind TEM8 can beprepared by any suitable method including, for example, cloning ofappropriate sequences or by direct chemical synthesis by methods such asthe phosphotriester method of Narang et al., Meth. Enzymol. 68:90-99,1979; the phosphodiester method of Brown et al., Meth. Enzymol.68:109-151, 1979; the diethylphosphoramidite method of Beaucage et al.,Tetra. Lett. 22:1859-1862, 1981; the solid phase phosphoramiditetriester method described by Beaucage & Caruthers, Tetra. Letts.22(20):1859-1862, 1981, for example, using an automated synthesizer asdescribed in, for example, Needham-VanDevanter et al., Nucl. Acids Res.12:6159-6168, 1984; and, the solid support method of U.S. Pat. No.4,458,066. Chemical synthesis produces a single strandedoligonucleotide. This can be converted into double stranded DNA byhybridization with a complementary sequence or by polymerization with aDNA polymerase using the single strand as a template. One of skill wouldrecognize that while chemical synthesis of DNA is generally limited tosequences of about 100 bases, longer sequences may be obtained by theligation of shorter sequences.

Exemplary nucleic acids can be prepared by cloning techniques. Examplesof appropriate cloning and sequencing techniques, and instructionssufficient to direct persons of skill through many cloning exercises areknown (see, e.g., Sambrook et al. (Molecular Cloning: A LaboratoryManual, 4^(th) ed, Cold Spring Harbor, N.Y., 2012) and Ausubel et al.(In Current Protocols in Molecular Biology, John Wiley & Sons, New York,through supplement 104, 2013). Product information from manufacturers ofbiological reagents and experimental equipment also provide usefulinformation. Such manufacturers include the SIGMA Chemical Company(Saint Louis, Mo.), R&D Systems (Minneapolis, Minn.), Pharmacia Amersham(Piscataway, N.J.), CLONTECH Laboratories, Inc. (Palo Alto, Calif.),Chem Genes Corp., Aldrich Chemical Company (Milwaukee, Wis.), GlenResearch, Inc., GIBCO BRL Life Technologies, Inc. (Gaithersburg, Md.),Fluka Chemica-Biochemika Analytika (Fluka Chemie AG, Buchs,Switzerland), Invitrogen (Carlsbad, Calif.), and Applied Biosystems(Foster City, Calif.), as well as many other commercial sources known toone of skill.

Nucleic acids can also be prepared by amplification methods.Amplification methods include polymerase chain reaction (PCR), theligase chain reaction (LCR), the transcription-based amplificationsystem (TAS), the self-sustained sequence replication system (3SR). Awide variety of cloning methods, host cells, and in vitro amplificationmethodologies are well known to persons of skill.

In some embodiments, the nucleic acid molecule encodes a CAR as providedherein for expression in a T cell to generate a chimeric antigenreceptor T cell. The nucleic acid molecule encoding the chimeric antigenbinding receptor can be included in a vector (such as a lentiviralvector) for expression in a host cell, such as a T cell. Exemplary cellsinclude a T cell, a Natural Killer (NK) cell, a cytotoxic T lymphocyte(CTL), and a regulatory T cell. Methods of generating nucleic acidmolecules encoding chimeric antigen receptors and T cells including suchreceptors are known in the art (see, e.g., Brentjens et al., 2010,Molecular Therapy, 18:4, 666-668; Morgan et al., 2010, MolecularTherapy, published online Feb. 23, 2010, pages 1-9; Till et al., 2008,Blood, 1 12:2261-2271; Park et al., Trends Biotechnol., 29:550-557,2011; Grupp et al., N Engl J Med., 368:1509-1518, 2013; Han et al., J.Hematol Oncol., 6:47, 2013; PCT Pub. WO2012/079000, WO2013/126726; andU.S. Pub. 2012/0213783, each of which is incorporated by referenceherein in its entirety.)

The nucleic acid molecules can be expressed in a recombinantlyengineered cell such as bacteria, plant, yeast, insect and mammaliancells. The antibodies, antigen binding fragments, and conjugates can beexpressed as individual V_(H) and/or V_(L) chain (linked to an effectormolecule or detectable marker as needed), or can be expressed as afusion protein. Methods of expressing and purifying antibodies andantigen binding fragments are known and further described herein (see,e.g., Al-Rubeai (ed), Antibody Expression and Production, SpringerPress, 2011). An immunoadhesin can also be expressed. Thus, in someexamples, nucleic acids encoding a V_(H) and V_(L), and immunoadhesinare provided. The nucleic acid sequences can optionally encode a leadersequence.

To create a scFv the V_(H)- and V_(L)-encoding DNA fragments can beoperatively linked to another fragment encoding a flexible linker, e.g.,encoding the amino acid sequence (Gly₄-Ser)₃, such that the V_(H) andV_(L) sequences can be expressed as a contiguous single-chain protein,with the V_(L) and V_(H) domains joined by the flexible linker (see,e.g., Bird et al., Science 242:423-426, 1988; Huston et al., Proc. Natl.Acad. Sci. USA 85:5879-5883, 1988; McCafferty et al., Nature348:552-554, 1990; Kontermann and Dubel (Ed), Antibody Engineering,Vols. 1-2, 2^(nd) Ed., Springer Press, 2010; Harlow and Lane,Antibodies: A Laboratory Manual, 2^(nd), Cold Spring Harbor Laboratory,New York, 2013). Optionally, a cleavage site can be included in alinker, such as a furin cleavage site.

The nucleic acid encoding a V_(H) and/or the V_(L) optionally can encodean Fc domain (immunoadhesin). The Fc domain can be an IgA, IgM or IgG Fcdomain. The Fc domain can be an optimized Fc domain, as described inU.S. Published Patent Application No. 2010/093979, incorporated hereinby reference. In one example, the immunoadhesin is an IgG₁ Fc.

The single chain antibody may be monovalent, if only a single V_(H) andV_(L) are used, bivalent, if two V_(H) and V_(L) are used, orpolyvalent, if more than two V_(H) and V_(L) are used. Bispecific orpolyvalent antibodies may be generated that bind specifically to TEM8and another antigen, such as, but not limited to, CD3. The encoded V_(H)and V_(L) optionally can include a furin cleavage site between the V_(H)and V_(L) domains.

Those of skill in the art are knowledgeable in the numerous expressionsystems available for expression of proteins including E. coli, otherbacterial hosts, yeast, and various higher eukaryotic cells such as theCOS, CHO, HeLa and myeloma cell lines.

One or more DNA sequences encoding the antibodies, antibody bindingfragments, conjugates, and CARs can be expressed in vitro by DNAtransfer into a suitable host cell. The cell may be prokaryotic oreukaryotic. The term also includes any progeny of the subject host cell.It is understood that all progeny may not be identical to the parentalcell since there may be mutations that occur during replication. Methodsof stable transfer, meaning that the foreign DNA is continuouslymaintained in the host, are known in the art. Hybridomas expressing theantibodies of interest are also encompassed by this disclosure.

Polynucleotide sequences encoding the antibody or antigen bindingfragment or conjugate thereof, can be operatively linked to expressioncontrol sequences. An expression control sequence operatively linked toa coding sequence is ligated such that expression of the coding sequenceis achieved under conditions compatible with the expression controlsequences. The expression control sequences include, but are not limitedto appropriate promoters, enhancers, transcription terminators, a startcodon (i.e., ATG) in front of a protein-encoding gene, splicing signalfor introns, maintenance of the correct reading frame of that gene topermit proper translation of mRNA, and stop codons.

To obtain high level expression of a cloned gene, it is desirable toconstruct expression cassettes which contain, at the minimum, a strongpromoter to direct transcription, a ribosome binding site fortranslational initiation (internal ribosomal binding sequences), and atranscription/translation terminator. For E. coli, this includes apromoter such as the T7, trp, lac, or lambda promoters, a ribosomebinding site, and preferably a transcription termination signal. Foreukaryotic cells, the control sequences can include a promoter and/or anenhancer derived from, for example, an immunoglobulin gene, HTLV, SV40or cytomegalovirus, and a polyadenylation sequence, and can furtherinclude splice donor and/or acceptor sequences (for example, CMV and/orHTLV splice acceptor and donor sequences). The cassettes can betransferred into the chosen host cell by well-known methods such astransformation or electroporation for E. coli and calcium phosphatetreatment, electroporation or lipofection for mammalian cells. Cellstransformed by the cassettes can be selected by resistance toantibiotics conferred by genes contained in the cassettes, such as theamp, gpt, neo and hyg genes.

The polynucleotide sequences encoding the antibody, or antigen bindingfragment or conjugate thereof can be inserted into an expression vectorincluding, but not limited to a plasmid, virus or other vehicle that canbe manipulated to allow insertion or incorporation of sequences and canbe expressed in either prokaryotes or eukaryotes. Hosts can includemicrobial, yeast, insect and mammalian organisms. Methods of expressingDNA sequences having eukaryotic or viral sequences in prokaryotes arewell known in the art. Biologically functional viral and plasmid DNAvectors capable of expression and replication in a host are known in theart.

When the host is a eukaryote, such methods of transfection of DNA ascalcium phosphate coprecipitates, conventional mechanical proceduressuch as microinjection, electroporation, insertion of a plasmid encasedin liposomes, or virus vectors may be used. Eukaryotic cells can also becotransformed with polynucleotide sequences encoding the antibody,labeled antibody, or HIV-1 Env binding fragment thereof, and a secondforeign DNA molecule encoding a selectable phenotype, such as the herpessimplex thymidine kinase gene. Another method is to use a eukaryoticviral vector, such as simian virus 40 (SV40) or bovine papilloma virus,to transiently infect or transform eukaryotic cells and express theprotein (see for example, Viral Expression Vectors, Springer press,Muzyczka ed., 2011). One of skill in the art can readily use anexpression systems such as plasmids and vectors of use in producingproteins in cells including higher eukaryotic cells such as the COS,CHO, HeLa and myeloma cell lines.

For purposes of producing a recombinant CAR, the host cell may be amammalian cell. The host cell may be a human cell. In some embodiments,the host cell may be a peripheral blood lymphocyte (PBL) or a peripheralblood mononuclear cell (PBMC), or a T cell. The T cell can be any Tcell, such as a cultured T cell, e.g., a primary T cell, or a T cellfrom a cultured T cell line, e.g., Jurkat, SupTl, etc., or a T cellobtained from a mammal. If obtained from a mammal, the T cell can beobtained from numerous sources, including but not limited to blood, bonemarrow, lymph node, the thymus, or other tissues or fluids. T cells canalso be enriched for or purified. The T cell may be a human T cell. TheT cell may be a T cell isolated from a human. The T cell can be any typeof T cell and can be of any developmental stage, including but notlimited to, CD4⁺/CD8⁺ double positive T cells, CD4⁺ helper T cells,e.g., Th₁ and Th₂ cells, CD8⁺ T cells (e.g., cytotoxic T cells), tumorinfiltrating cells, memory T cells, naive T cells, and the like. The Tcell may be a CD8⁺ T cell or a CD4⁺ T cell.

Also provided is a population of cells comprising at least one host celldescribed herein. The population of cells can be a heterogeneouspopulation comprising the host cell comprising any of the recombinantexpression vectors described, in addition to at least one other cell,e.g., a host cell (e.g., a T cell), which does not comprise any of therecombinant expression vectors, or a cell other than a T cell, e.g., a Bcell, a macrophage, a neutrophil, an erythrocyte, a hepatocyte, anendothelial cell, an epithelial cell, a muscle cell, a brain cell, etc.Alternatively, the population of cells can be a substantiallyhomogeneous population, in which the population comprises mainly hostcells (e.g., consisting essentially of) comprising the recombinantexpression vector. The population also can be a clonal population ofcells, in which all cells of the population are clones of a single hostcell comprising a recombinant expression vector, such that all cells ofthe population comprise the recombinant expression vector. In oneembodiment of the invention, the population of cells is a clonalpopulation comprising host cells comprising a recombinant expressionvector as described herein

Modifications can be made to a nucleic acid encoding a polypeptidedescribed herein without diminishing its biological activity. Somemodifications can be made to facilitate the cloning, expression, orincorporation of the targeting molecule into a fusion protein. Suchmodifications are well known to those of skill in the art and include,for example, termination codons, a methionine added at the aminoterminus to provide an initiation, site, additional amino acids placedon either terminus to create conveniently located restriction sites, oradditional amino acids (such as poly His) to aid in purification steps.In addition to recombinant methods, the immunoconjugates, effectormoieties, and antibodies of the present disclosure can also beconstructed in whole or in part using standard peptide synthesis wellknown in the art.

Once expressed, the antibodies, antigen binding fragments, andconjugates can be purified according to standard procedures in the art,including ammonium sulfate precipitation, affinity columns, columnchromatography, and the like (see, generally, Simpson ed., Basic methodsin Protein Purification and Analysis: A laboratory Manual, Cold HarborPress, 2008). The antibodies, antigen binding fragment, and conjugatesneed not be 100% pure. Once purified, partially or to homogeneity asdesired, if to be used therapeutically, the polypeptides should besubstantially free of endotoxin.

Methods for expression of the antibodies, antigen binding fragments, andconjugates, and/or refolding to an appropriate active form, frommammalian cells, and bacteria such as E. coli have been described andare well-known and are applicable to the antibodies disclosed herein.See, e.g., Harlow and Lane, Antibodies: A Laboratory Manual, 2^(nd),Cold Spring Harbor Laboratory, New York, 2013, Simpson ed., Basicmethods in Protein Purification and Analysis: A laboratory Manual, ColdHarbor Press, 2008, and Ward et al., Nature 341:544, 1989.

Often, functional heterologous proteins from E. coli or other bacteriaare isolated from inclusion bodies and require solubilization usingstrong denaturants, and subsequent refolding. During the solubilizationstep, as is well known in the art, a reducing agent must be present toseparate disulfide bonds. An exemplary buffer with a reducing agent is:0.1 M Tris pH 8, 6 M guanidine, 2 mM EDTA, 0.3 M DTE (dithioerythritol).Reoxidation of the disulfide bonds can occur in the presence of lowmolecular weight thiol reagents in reduced and oxidized form, asdescribed in Saxena et al., Biochemistry 9: 5015-5021, 1970, andespecially as described by Buchner et al., supra.

In addition to recombinant methods, the antibodies, antigen bindingfragments, and/or conjugates can also be constructed in whole or in partusing standard peptide synthesis. Solid phase synthesis of thepolypeptides can be accomplished by attaching the C-terminal amino acidof the sequence to an insoluble support followed by sequential additionof the remaining amino acids in the sequence. Techniques for solid phasesynthesis are described by Barany & Merrifield, The Peptides: Analysis,Synthesis, Biology. Vol. 2: Special Methods in Peptide Synthesis, PartA. pp. 3-284; Merrifield et al., J. Am. Chem. Soc. 85:2149-2156, 1963,and Stewart et al., Solid Phase Peptide Synthesis, 2nd ed., Pierce Chem.Co., Rockford, Ill., 1984. Proteins of greater length may be synthesizedby condensation of the amino and carboxyl termini of shorter fragments.Methods of forming peptide bonds by activation of a carboxyl terminalend (such as by the use of the coupling reagent N,N′-dicylohexylcarbodimide) are well known in the art.

E. Methods of Detection

Methods are provided for detecting the presence of a cell that expressesTEM8 in a subject. In some embodiments, the methods include contacting acell from a subject with one or more of the antibodies that specificallybind TEM8 or conjugate thereof to form an immune complex. The presence(or absence) of the immune complex is then detected. The presence of theimmune complex indicates the presence of a cell that expresses TEM8 inthe subject. The detection methods can involve in vivo detection or invitro detection of the immune complex. In several embodiments, detectionof a cell that expresses TEM8 includes detecting cell-surface expressionof TEM8 on the endothelial cell. In several embodiments of the providedmethods, detecting a cell that expresses TEM8 in a subject detectspathological angiogenesis in the subject, for example angiogenesisassociated with tumor development. The cell can be an endothelial cellor a pericyte, for example.

Thus, methods are provided for detecting a cell that expresses TEM8, forexample, an endothelial cell that expresses TEM8 or a pericyte thatexpresses TEM8. In a specific non-limiting example, the cell is anendothelial cell. In some embodiments, a subject is selected who has, issuspected of having, or is at risk of developing, a tumor, for example,a carcinoma. For example, the subject has, is suspected of having, or isat risk of developing breast carcinoma, lung carcinoma, colorectalcarcinoma or melanoma. In some examples the subject has, is suspected ofhaving, or is at risk of developing, breast, colorectal, lung or skincancer. Thus, the presence of an endothelial cell expressing TEM8 can bedetected in these subjects. In some examples, detecting an endothelialcell that expresses TEM8 detects a blood vessel comprising at least oneendothelial cell that expresses TEM8. In some examples, the endothelialcell is a vascular endothelial cell, for example a vascular endothelialcell in a tumor associated blood vessel.

In one embodiment, a sample is obtained from a subject, and the presenceof an endothelial cell that expresses TEM8 is assessed in vitro. Forexample, such methods include contacting an endothelial cell in abiological sample from the subject with one or more of the conjugates orantibodies provided herein that specifically bind TEM8 or an antigenbinding fragment thereof to form an immune complex. The presence (orabsence) of the immune complex is then detected. The presence of theimmune complex on the endothelial cell from the subject indicates thepresence of an endothelial cell that expresses TEM8 in the subject. Forexample, an increase in the presence of the immune complex in the sampleas compared to formation of the immune complex in a control sampleindicates the presence of an endothelial cell that expresses TEM8 in thesubject.

A biological sample is typically obtained from a mammalian subject ofinterest, such as human. The sample can be any sample, including, butnot limited to, tissue from biopsies, autopsies and pathology specimens.Biological samples also include sections of tissues, for example, frozensections taken for histological purposes.

In some examples of the disclosed methods, the TEM8 specific antibody orantigen binding fragment is conjugated to a detectable marker. In someexamples, the methods further include contacting a second antibody thatspecifically binds the TEM8 specific antibody, antigen binding fragmentthereof, or a conjugate including these molecules, for a sufficientamount of time to form an immune complex and detecting this immunecomplex. An increase in the presence of this immune complex in abiological sample from a selected subject (as described above) comparedto the presence of the immune complex in a control sample or otherstandard detects the presence of an endothelial cell that expresses TEM8in the biological sample. In some examples, the second antibody isconjugated to a detectable marker.

Suitable detectable markers for the antibody or secondary antibody aredescribed and known to the skilled artisan. For example, variousenzymes, prosthetic groups, fluorescent materials, luminescentmaterials, magnetic agents and radioactive materials. Non-limitingexamples of suitable enzymes include horseradish peroxidase, alkalinephosphatase, beta-galactosidase, or acetylcholinesterase. Non-limitingexamples of suitable prosthetic group complexes includestreptavidin/biotin and avidin/biotin. Non-limiting examples of suitablefluorescent materials include umbelliferone, fluorescein, fluoresceinisothiocyanate, rhodamine, dichlorotriazinylamine fluorescein, dansylchloride or phycoerythrin. A non-limiting exemplary luminescent materialis luminol; a non-limiting exemplary a magnetic agent is gadolinium, andnon-limiting exemplary radioactive labels include ¹²⁵I, ¹³¹I, ³⁵S or ³H.

The antibodies that specifically bind TEM8 and conjugates thereof can beused in immunohistochemical assays. These assays are well known to oneof skill in the art (see Harlow & Lane, Antibodies, A Laboratory Manual,2^(nd) ed., Cold Spring Harbor Publications, New York (2013), for adescription of immunoassay formats

The antibodies disclosed herein can also be used to detect endothelialcells that express TEM8 as well as pericytes that express TEM8 in vivo.In some example, in vivo detection of an endothelial cell that expressesTEM8 detects pathological angiogenesis in the subject. Thus, methods aredisclosed for detecting pathological angiogenesis in a subject, such aspathological angiogenesis associated with a tumor, such as a carcinoma;for example, a breast carcinoma, lung carcinoma, colorectal carcinoma ormelanoma. In one embodiment, an effective amount of an antibody thatspecifically binds to TEM8 (or antigen binding fragment thereof) or aconjugate thereof is administered to the subject for a sufficient amountof time for the antibody or antigen binding fragment to form an immunecomplex, which can then be detected. Detection of the immune complex inthe subject determines the presence of an endothelial cell thatexpresses TEM8, which detects pathological angiogenesis in the subject.In one specific, non-limiting example detection of an immune complex isperformed by immunoscintography. Other specific, non-limiting examplesof immune complex detection include radiolocalization, radioimaging,magnetic resonance imaging (such as using a biotinylated antibody andavidin-iron oxide), positron emission tomography (such as using an¹¹¹indium-labeled monoclonal antibody) or fluorescence imaging (such asusing luciferase or green fluorescent protein labeled antibodies). SeePaty et al., Transplantation., 77:1133-1137, 2004, herein incorporatedby reference. In several examples, the disclosed method detectsendothelial cells lining the inner wall of blood vessels in a tumor inthe subject, for example, a breast carcinoma, lung carcinoma, colorectalcarcinoma or melanoma.

In the setting of magnetic resonance imaging, contrast agent detectioncan be greatly impacted by magnetic resonance scanner field strength.Increased field strengths provide improvements by orders of magnitude inthe ability to detect contrast agents (Hu et al., Ann. Rev. Biomed.Eng., 6:157-184, 2004; Wedeking et al., Magn. Reson. Imaging.,17:569-575, 1999). For example, the limit of detection of gadolinium at2 tesla (T) is ˜30 μM. At 4T the limit of detection is reduced to ˜1 μM.With newly available 7 to 12T scanners one would expect to detect low(10-100) nM concentrations of this contrast agent. Similar sensitivitycan also be identified using contrast agents such as iron oxide. Oncedetected the test results can be used to assist in or guide surgical orother excision of a tumor.

In one embodiment, an effective amount of an antibody or antigen bindingfragment that specifically binds to TEM8 or a conjugate thereof isadministered to a subject having a tumor following anti-cancer oranti-angiogenic treatment. After a sufficient amount of time has elapsedto allow for the administered antibody or antigen binding fragment orconjugate to form an immune complex with TEM8 on an endothelial cell,the immune complex is detected. For example, an antibody thatspecifically binds to TEM8 or conjugate thereof can be administered to asubject prior to, or following, treatment of a tumor. The tumor can be(but is not limited to) a breast, colorectal, lung or skin cancer. Thepresence (or absence) of the immune complex indicates the effectivenessof the treatment. For example, an increase in the immune complexcompared to a control taken prior to the treatment indicates that thetreatment is not effective, whereas a decrease in the immune complexcompared to a control taken prior to the treatment indicates that thetreatment is effective.

F. Methods of Treatment

A therapeutically effective amount of an antibody or antigen bindingfragment that specifically binds TEM8 or conjugate thereof or CAR T cellexpressing an antigen binding fragment that specifically binds TEM8 canbe administered to a subject to treat pathological angiogenesis, forexample to treat a tumor, for example a carcinoma. In some embodiments,administration of a therapeutically effective amount of an antibody orantigen binding fragment that specifically binds TEM8 or conjugatethereof or CAR T cell expressing an antigen binding fragment thatspecifically binds TEM8 decreases pathological angiogenesis, such aspathological angiogenesis that occurs in various types of cancer, suchas breast, colorectal, lung or skin cancer, or with maculardegeneration. Thus, a subject can be selected for treatment that has, issuspected of having or is at risk of developing a tumor, such as acarcinoma.

In some examples, the antibodies, antigen binding fragments, CAR Tcells, compositions and conjugates disclosed herein can be administeredto a subject to decrease pathological angiogenesis in the subject, toslow or inhibit the growth or metastasis of a tumor, or treat corneal orretinal degeneration. In these applications, a therapeutically effectiveamount of an antibody or antigen binding fragment that specificallybinds TEM8 or a conjugate or CAR T cells or composition is administeredto a subject in an amount and under conditions sufficient to form animmune complex with TEM8, thereby slowing or inhibiting the growth orthe metastasis of a tumor, or other pathological angiogenesis, or toinhibit a sign or a symptom of a cancer. Examples of suitable subjectsinclude those diagnosed with or suspecting of having cancer (forexample, a subject having a tumor), for example subjects having acarcinoma, such as a breast carcinoma, lung carcinoma, colorectalcarcinoma or melanoma.

The therapeutically effective amount will depend upon the severity ofthe disease and the general state of the patient's health. Atherapeutically effective amount is that which provides eithersubjective relief of a symptom(s) or an objectively identifiableimprovement as noted by the clinician or other qualified observer. Inone embodiment, a therapeutically effective amount is the amountnecessary to inhibit tumor growth (such as growth of a breast carcinoma,lung carcinoma, colorectal carcinoma or melanoma), pathologicalangiogenesis, or the amount that is effective at reducing a sign or asymptom of the tumor. The therapeutically effective amount of the agentsadministered can vary depending upon the desired effects and the subjectto be treated. In some examples, therapeutic amounts are amounts whicheliminate or reduce the patient's tumor burden, or which prevent orreduce the proliferation of metastatic cells, or which prevent or reducepathological angiogenesis.

Subjects that can benefit from the disclosed methods include human andveterinary subjects. Subjects can be screened prior to initiating thedisclosed therapies, for example to determine whether the subject has atumor or pathological angiogenesis, or both. The presence of a tumor orpathological angiogenesis, or both, indicates that the tumor orpathological angiogenesis can be treated using the methods providedherein.

Any method of administration can be used for the disclosed antibodies,antigen binding fragments, conjugates, compositions and additionalagents, including local and systemic administration. For exampletopical, oral, intravascular such as intravenous, intramuscular,intraperitoneal, intranasal, intradermal, intrathecal and subcutaneousadministration can be used. The particular mode of administration andthe dosage regimen will be selected by the attending clinician, takinginto account the particulars of the case (for example the subject, thedisease, the disease state involved, and whether the treatment isprophylactic). In cases in which more than one agent or composition isbeing administered, one or more routes of administration may be used;for example, a chemotherapeutic agent may be administered orally and anantibody or antigen binding fragment or conjugate or composition may beadministered intravenously. Methods of administration include injectionfor which the conjugates, antibodies, antigen binding fragments, orcompositions are provided in a nontoxic pharmaceutically acceptablecarrier such as water, saline, Ringer's solution, dextrose solution, 5%human serum albumin, fixed oils, ethyl oleate, or liposomes. In someembodiments, local administration of the disclosed compounds can beused, for instance by applying the antibody or antigen binding fragmentto a region of tissue from which a tumor has been removed, or a regionsuspected of being prone to tumor development. In some embodiments,sustained intra-tumoral (or near-tumoral) release of the pharmaceuticalpreparation that includes a therapeutically effective amount of theantibody or antigen binding fragment may be beneficial. In otherexamples, the conjugate is applied as an eye drop topically to thecornea, or intravitreally into the eye.

The compositions that include an antibody or antigen binding fragment orconjugate thereof or CAR T cells can be formulated in unit dosage formsuitable for individual administration of precise dosages. In addition,the compositions may be administered in a single dose or in a multipledose schedule. A multiple dose schedule is one in which a primary courseof treatment may be with more than one separate dose, for instance 1-10doses, followed by other doses given at subsequent time intervals asneeded to maintain or reinforce the action of the compositions.Treatment can involve daily or multi-daily doses of compound(s) over aperiod of a few days to months, or even years. Thus, the dosage regimewill also, at least in part, be determined based on the particular needsof the subject to be treated and will be dependent upon the judgment ofthe administering practitioner.

Typical dosages of the antibodies, conjugates, compositions oradditional agents can range from about 0.01 to about 30 mg/kg, such asfrom about 0.1 to about 10 mg/kg. In some examples, the dosage is atleast about 0.1 mg/kg, at least about 0.2 mg/kg, at least about 0.3mg/kg, at least about 0.4 mg/kg, at least about 0.5 mg/kg, at leastabout 1 mg/kg, at least about 4 mg/kg, at least about 3 mg/kg, at leastabout 5 mg/kg, at least about 6 mg/kg, at least about 7 mg/kg, at leastabout 8 mg/kg is at least about 9 mg/kg, at least about 10 mg/kg, atleast about 11 mg/kg, at least about 12 mg/kg, at least about 13 mg/kg,at least about 14 mg/kg, at least about 15 mg/kg, at least about 16mg/kg, at least about 17 mg/kg, at least about 18 mg/kg, at least about19 mg/kg, at least about 20 mg/kg, at least about 21 mg/kg, at leastabout 22 mg/kg, at least about 23 mg/kg, at least about 24 mg/kg atleast about 25 mg/kg, at least about 26 mg/kg, at least about 27 mg/kg,at least about 28 mg/kg, at least about 29 mg/kg, or at least about 30mg/kg.

In particular examples, the subject is administered a therapeuticcomposition that includes one or more of the conjugates, antibodies,compositions, CAR T cells or additional agents, on a multiple dailydosing schedule, such as at least two consecutive days, 10 consecutivedays, and so forth, for example for a period of weeks, months, or years.In one example, the subject is administered the conjugates, antibodies,compositions or additional agents for a period of at least 30 days, suchas at least 2 months, at least 4 months, at least 6 months, at least 12months, at least 24 months, or at least 36 months.

In some embodiments, a disclosed therapeutic agent is administered maybe administered intravenously, subcutaneously or by another mode dailyor multiple times per week for a period of time, followed by a period ofno treatment, then the cycle is repeated. In some embodiments, theinitial period of treatment (e.g., administration of the therapeuticagent daily or multiple times per week) is for 3 days, 1 week, 2 weeks,3 weeks, 4 weeks, 5 weeks, 6 weeks, 7 weeks, 8 weeks, 9 weeks, 10 weeks,11 weeks or 12 weeks. In a related embodiment, the period of notreatment lasts for 3 days, 1 week, 2 weeks, 3 weeks or 4 weeks. Incertain embodiments, the dosing regimen of the therapeutic agent isdaily for 3 days followed by 3 days off; or daily or multiple times perweek for 1 week followed by 3 days or 1 week off; or daily or multipletimes per week for 2 weeks followed by 1 or 2 weeks off; or daily ormultiple times per week for 3 weeks followed by 1, 2 or 3 weeks off; ordaily or multiple times per week for 4, 5, 6, 7, 8, 9, 10, 11 or 12weeks followed by 1, 2, 3 or 4 weeks off.

In additional embodiments, the antibodies, compositions and conjugatesthat specifically bind TEM8 can be used to decrease binding of AnthraxPA to a cell. For example, an effective amount of the providedantibodies, compositions and conjugates can be incubated with a cellunder conditions sufficient to form an immune complex with TEM8, therebydecreasing binding of Anthrax PA to the cell. In some examples, aneffective amount of the antibodies, compositions and conjugates thatspecifically bind TEM8 can be administered to a subject to decreasebinding of Anthrax PA to a cell in the subject. Suitable subjects mayinclude those diagnosed or at risk of developing with Anthrax infectionor suspected of exposure to Anthrax.

Administration of the antibodies, antigen binding fragments, conjugates,CAR T cells, or compositions can be accompanied by administration ofother anti-cancer or anti-angiogenesis agents or therapeutic treatments(such as surgical resection of a tumor or radiation therapy). Forexample, prior to, during, or following administration of a therapeuticamount of the antibodies or conjugates, the subject can receive one ormore additional therapies. In one example, the subject receives one ormore treatments to remove or reduce the tumor or pathologicalangiogenesis prior to administration of a therapeutic amount of one ormore agents for treatment of the tumor or pathological angiogenesis. Forexample, the additional agent may include, but is not limited to, achemotherapeutic agent, an anti-angiogenic agent, or a combinationthereof. In another example, at least part of the tumor is surgically orotherwise excised or reduced in size or volume prior to administeringthe therapeutically effective amount of the antibody or antigen bindingfragment or conjugate.

Particular examples of additional therapeutic agents that can be usedinclude microtubule binding agents, DNA intercalators or cross-linkers,DNA synthesis inhibitors, DNA and RNA transcription inhibitors,antibodies, enzymes, enzyme inhibitors, gene regulators, andangiogenesis inhibitors. These agents (which are administered at atherapeutically effective amount) and treatments can be used alone or incombination. For example, any suitable anti-cancer or anti-angiogenicagent can be administered in combination with the antibodies, conjugatesdisclosed herein. Methods and therapeutic dosages of such agents areknown to those skilled in the art, and can be determined by a skilledclinician. In one example the chemotherapeutic agent includes 5-FU orIRT or both.

Microtubule binding agent refers to an agent that interacts with tubulinto stabilize or destabilize microtubule formation thereby inhibitingcell division. Examples of microtubule binding agents that can be usedin conjunction with the disclosed therapy include, without limitation,paclitaxel, docetaxel, vinblastine, vindesine, vinorelbine (navelbine),the epothilones, colchicine, dolastatin 15, nocodazole, podophyllotoxinand rhizoxin. Analogs and derivatives of such compounds also can be usedand are known to those of ordinary skill in the art. For example,suitable epothilones and epothilone analogs are described inInternational Publication No. WO 2004/018478. Taxoids, such aspaclitaxel and docetaxel, as well as the analogs of paclitaxel taught byU.S. Pat. Nos. 6,610,860; 5,530,020; and 5,912,264, can be used.

Suitable DNA and RNA transcription regulators, including, withoutlimitation, actinomycin D, daunorubicin, doxorubicin and derivatives andanalogs thereof also are suitable for use in combination with thedisclosed therapies. DNA intercalators and cross-linking agents that canbe administered to a subject include, without limitation, cisplatin,carboplatin, oxaliplatin, mitomycins, such as mitomycin C, bleomycin,chlorambucil, cyclophosphamide and derivatives and analogs thereof. DNAsynthesis inhibitors suitable for use as therapeutic agents include,without limitation, methotrexate, 5-fluoro-5′-deoxyuridine, 5-FU andanalogs thereof. Examples of suitable enzyme inhibitors include, withoutlimitation, camptothecin, etoposide, formestane, trichostatin andderivatives and analogs thereof. Suitable compounds that affect generegulation include agents that result in increased or decreasedexpression of one or more genes, such as raloxifene, 5-azacytidine,5-aza-2′-deoxycytidine, tamoxifen, 4-hydroxytamoxifen, mifepristone andderivatives and analogs thereof.

Examples of the commonly used chemotherapy drugs include Adriamycin,Alkeran, Ara-C, BiCNU, Busulfan, CCNU, Carboplatinum, Cisplatinum,Cytoxan, Daunorubicin, DTIC, 5-FU, Fludarabine, Hydrea, Idarubicin,Ifosfamide, Methotrexate, Mithramycin, Mitomycin, Mitoxantrone, NitrogenMustard, Taxol (or other taxanes, such as docetaxel), Velban,Vincristine, VP-16, while some more newer drugs include Gemcitabine(Gemzar), Herceptin, IRT (Camptosar, CPT-11), Leustatin, Navelbine,Rituxan STI-571, Taxotere, Topotecan (Hycamtin), Xeloda (Capecitabine),Zevelin and calcitriol.

Non-limiting examples of immunomodulators that can be used includeAS-101 (Wyeth-Ayerst Labs.), bropirimine (Upjohn), gamma interferon(Genentech), GM-CSF (granulocyte macrophage colony stimulating factor;Genetics Institute), IL-2 (Cetus or Hoffman-LaRoche), human immuneglobulin (Cutter Biological), IMREG (from Imreg of New Orleans, La.),SK&F 106528, and TNF (tumor necrosis factor; Genentech).

Thus, non-limiting examples of chemotherapeutic agents for use incombination with the disclosed TEM8 specific antibodies, antigen bindingfragments, or conjugates thereof, include chemotherapeutic agents suchas erlotinib (TARCEVA®, Genentech/OSI Pharm.), bortezomib (VELCADE®,Millenium Pharm.), fulvestrant (FASLODEX®, AstraZeneca), sutent(SU11248, Pfizer), letrozole (FEMARA®, Novartis), imatinib mesylate(GLEEVEC®, Novartis), PTK787/ZK 222584 (Novartis), oxaliplatin(Eloxatin®, Sanofi), 5-FU (5-fluorouracil), leucovorin, Rapamycin(Sirolimus, RAPAMUNE®, Wyeth), lapatinib (TYKERB®, GSK572016,GlaxoSmithKline), lonafarnib (SCH 66336), sorafenib (BAY43-9006, BayerLabs.), and gefitinib (IRESSA®, AstraZeneca), AG1478, AG1571 (SU 5271;Sugen), alkylating agents such as thiotepa and CYTOXAN®cyclosphosphamide; alkyl sulfonates such as busulfan, improsulfan andpiposulfan; antifolate antineoplastic such as pemetrexed (ALIMTA® EliLilly), aziridines such as benzodopa, carboquone, meturedopa, anduredopa; ethylenimines and methylamelamines including altretamine,triethylenemelamine, triethylenephosphoramide,triethylenethiophosphoramide and trimethylomelamine; acetogenins(especially bullatacin and bullatacinone); a camptothecin (including thesynthetic analogue topotecan); bryostatin; callystatin; CC-1065(including its adozelesin, carzelesin and bizelesin syntheticanalogues); cryptophycins (particularly cryptophycin 1 and cryptophycin8); dolastatin; duocarmycin (including the synthetic analogues, KW-2189and CB1-TM1); eleutherobin; pancratistatin; a sarcodictyin;spongistatin; nitrogen mustards such as chlorambucil, chlornaphazine,cholophosphamide, estramustine, ifosfamide, mechlorethamine,mechlorethamine oxide hydrochloride, melphalan, novembichin,phenesterine, prednimustine, trofosfamide, uracil mustard; nitrosoureassuch as carmustine, chlorozotocin, fotemustine, lomustine, nimustine,and ranimnustine; antibiotics such as the enediyne antibiotics,calicheamicin, calicheamicin gamma1I and calicheamicin omegaI1;dynemicin, including dynemicin A; bisphosphonates, such as clodronate;an esperamicin; as well as neocarzinostatin chromophore and relatedchromoprotein enediyne antibiotic chromophores, aclacinomysins,actinomycin, anthramycin, azaserine, bleomycins, cactinomycin,carabicin, carminomycin, carzinophilin, chromomycinis, dactinomycin,daunorubicin, detorubicin, 6-diazo-5-oxo-L-norleucine, ADRIAMYCIN®doxorubicin (including morpholino-doxorubicin,cyanomorpholino-doxorubicin, 2-pyrrolino-doxorubicin anddeoxydoxorubicin), epirubicin, esorubicin, idarubicin, marcellomycin,mitomycins such as mitomycin C, mycophenolic acid, nogalamycin,olivomycins, peplomycin, potfiromycin, puromycin, quelamycin,rodorubicin, streptonigrin, streptozocin, tubercidin, ubenimex,zinostatin, zorubicin; anti-metabolites such as methotrexate and5-fluorouracil (5-FU); folic acid analogues such as denopterin,methotrexate, pteropterin, trimetrexate; purine analogs such asfludarabine, 6-mercaptopurine, thiamiprine, thioguanine; pyrimidineanalogs such as ancitabine, azacitidine, 6-azauridine, carmofur,cytarabine, dideoxyuridine, doxifluridine, enocitabine, floxuridine;androgens such as calusterone, dromostanolone propionate, epitiostanol,mepitiostane, testolactone; anti-adrenals such as aminoglutethimide,mitotane, trilostane; folic acid replenisher such as frolinic acid;aceglatone; aldophosphamide glycoside; aminolevulinic acid; eniluracil;amsacrine; bestrabucil; bisantrene; edatraxate; defofamine; demecolcine;diaziquone; elfornithine; elliptinium acetate; an epothilone; etoglucid;gallium nitrate; hydroxyurea; lentinan; lonidainine; maytansinoids suchas maytansine and ansamitocins; mitoguazone; mitoxantrone; mopidanmol;nitraerine; pentostatin; phenamet; pirarubicin; losoxantrone;podophyllinic acid; 2-ethylhydrazide; procarbazine; PSK® polysaccharidecomplex (JHS Natural Products, Eugene, Oreg.); razoxane; rhizoxin;sizofiran; spirogermanium; tenuazonic acid; triaziquone;2,2′,2″-trichlorotriethylamine; trichothecenes (especially T-2 toxin,verracurin A, roridin A and anguidine); urethan; vindesine; dacarbazine;mannomustine; mitobronitol; mitolactol; pipobroman; gacytosine;arabinoside (“Ara-C”); cyclophosphamide; thiotepa; taxoids, for example,paclitaxel (TAXOL®, Bristol-Myers Squibb Oncology, Princeton, N.J.),ABRAXANE™ Cremophor-free, albumin, nanoparticle formulation ofpaclitaxel (American Pharmaceutical Partners, Schaumberg, Ill.), andTAXOTERE® doxetaxel (Rhone-Poulenc Rorer, Antony, France); chloranbucil;GEMZAR® gemcitabine; 6-thioguanine; mercaptopurine; methotrexate;platinum analogs such as cisplatin and carboplatin; vinblastine;platinum; etoposide (VP-16); ifosfamide; mitoxantrone; vincristine;NAVELBINE® vinorelbine; novantrone; teniposide; edatrexate; daunomycin;aminopterin; xeloda; ibandronate; CPT-11; topoisomerase inhibitor RFS2000; difluorometlhylornithine (DMFO); retinoids such as retinoic acid;capecitabine; and pharmaceutically acceptable salts, acids orderivatives of any of the above.

Non-limiting examples of anti-angiogenic agents include molecules, suchas proteins, enzymes, polysaccharides, oligonucleotides, DNA, RNA, andrecombinant vectors, and small molecules that function to reduce or eveninhibit blood vessel growth. Examples of suitable angiogenesisinhibitors include, without limitation, angiostatin K1-3, staurosporine,genistein, fumagillin, medroxyprogesterone, suramin, interferon-alpha,metalloproteinase inhibitors, platelet factor 4, somatostatin,thromobospondin, endostatin, thalidomide, and derivatives and analogsthereof. For example, in some embodiments the anti-angiogenesis agent isan antibody that specifically binds to VEGF (for example, AVASTIN®,Roche) or a VEGF receptor (for example, a VEGFR2 antibody). In oneexample the anti-angiogenic agent includes a VEGFR2 antibody, or DMXAA(also known as Vadimezan or ASA404; available commercially, for example,from Sigma Corp., St. Louis, Mo.) or both. Exemplary kinase inhibitorsinclude GLEEVAC®, IRESSA®, and TARCEVA® that prevent phosphorylation andactivation of growth factors. Antibodies that can be used includeHERCEPTIN® and AVASTIN® that block growth factors and the angiogenicpathway.

In some examples, the additional agent is a monoclonal antibody, forexample, 3F8, Abagovomab, Adecatumumab, Afutuzumab, Alacizumab,Alemtuzumab, Altumomab pentetate, Anatumomab mafenatox, Apolizumab,Arcitumomab, Bavituximab, Bectumomab, Belimumab, Besilesomab,Bevacizumab, Bivatuzumab mertansine, Blinatumomab, Brentuximab vedotin,Cantuzumab mertansine, Capromab pendetide, Catumaxomab, CC49, Cetuximab,Citatuzumab bogatox, Cixutumumab, Clivatuzumab tetraxetan, Conatumumab,Dacetuzumab, Detumomab, Ecromeximab, Eculizumab, Edrecolomab,Epratuzumab, Ertumaxomab, Etaracizumab, Farletuzumab, Figitumumab,Galiximab, Gemtuzumab ozogamicin, Girentuximab, Glembatumumab vedotin,Ibritumomab tiuxetan, Igovomab, Imciromab, Intetumumab, Inotuzumabozogamicin, Ipilimumab, Iratumumab, Labetuzumab, Lexatumumab,Lintuzumab, Lorvotuzumab mertansine, Lucatumumab, Lumiliximab,Mapatumumab, Matuzumab, Mepolizumab, Metelimumab, Milatuzumab,Mitumomab, Morolimumab, Nacolomab tafenatox, Naptumomab estafenatox,Necitumumab, Nimotuzumab, Nofetumomab merpentan, Ofatumumab, Olaratumab,Oportuzumab monatox, Oregovomab, Panitumumab, Pemtumomab, Pertuzumab,Pintumomab, Pritumumab, Ramucirumab, Rilotumumab, Rituximab,Robatumumab, Satumomab pendetide, Sibrotuzumab, Sonepcizumab, sorafenib,sunitinib, Tacatuzumab tetraxetan, Taplitumomab paptox, Tenatumomab,TGN1412, Ticilimumab (=tremelimumab), Tigatuzumab, TNX-650, Trastuzumab,Tremelimumab, Tucotuzumab celmoleukin, Veltuzumab, Volociximab,Votumumab, Zalutumumab.

Another common treatment for some types of cancer is surgical treatment,for example surgical resection of the cancer or a portion of it. Anotherexample of a treatment is radiotherapy, for example administration ofradioactive material or energy (such as external beam therapy) to thetumor site to help eradicate the tumor or shrink it prior to surgicalresection.

Other therapeutic agents, for example anti-tumor agents, that may or maynot fall under one or more of the classifications above, also aresuitable for administration in combination with the disclosed therapies.By way of example, such agents include adriamycin, apigenin, rapamycin,zebularine, cimetidine, and derivatives and analogs thereof.

Preparation and dosing schedules for the additional agent may be usedaccording to manufacturer's instructions or as determined empirically bythe skilled practitioner. Preparation and dosing schedules for suchchemotherapy are also described in Chemotherapy Service, (1992) Ed., M.C. Perry, Williams & Wilkins, Baltimore, Md.

The combination therapy may provide synergy and prove synergistic, thatis, the effect achieved when the active ingredients used together isgreater than the sum of the effects that results from using thecompounds separately. A synergistic effect may be attained when theactive ingredients are: (1) co-formulated and administered or deliveredsimultaneously in a combined, unit dosage formulation; (2) delivered byalternation or in parallel as separate formulations; or (3) by someother regimen. When delivered in alternation, a synergistic effect maybe attained when the compounds are administered or deliveredsequentially, for example by different injections in separate syringes.In general, during alternation, an effective dosage of each activeingredient is administered sequentially, i.e. serially, whereas incombination therapy, effective dosages of two or more active ingredientsare administered together.

G. Compositions

Compositions are provided that include one or more of the disclosedconjugates, antibodies, or antigen binding fragments that specificallybind TEM8, or nucleic acid molecules or CARs, in a carrier (such as apharmaceutically acceptable carrier). The compositions can be preparedin unit dosage forms for administration to a subject. The amount andtiming of administration are at the discretion of the treating clinicianto achieve the desired outcome. The compositions can be formulated forsystemic (such as intravenus) or local (such as intra-tumor)administration. In one example, the antibody that specifically bindsTEM8 or an antigen binding fragment thereof, or conjugate including suchan antibody or antigen binding fragment, is formulated for parenteraladministration, such as intravenous administration. Compositionsincluding a conjugate, antibody or antigen binding fragment as disclosedherein are of use, for example, for the treatment and detection of atumor, for example a tumor occurring in breast, colorectal, lung or skincancer. In some examples, the compositions are useful for the treatmentor detection of a carcinoma. The compositions including a conjugate,antibody or antigen binding fragment as disclosed herein are also ofuse, for example, for the detection of pathological angiogenesis. Thecompositions including a conjugate, antibody or antigen binding fragmentas disclosed herein are also of use, for example, for inhibiting thebinding of Anthrax PA to TEM8.

The compositions for administration can include a solution of theconjugate, antibody or antigen binding fragment dissolved in apharmaceutically acceptable carrier, such as an aqueous carrier. Avariety of aqueous carriers can be used, for example, buffered salineand the like. These solutions are sterile and generally free ofundesirable matter. These compositions may be sterilized byconventional, well known sterilization techniques. The compositions maycontain pharmaceutically acceptable auxiliary substances as required toapproximate physiological conditions such as pH adjusting and bufferingagents, toxicity adjusting agents and the like, for example, sodiumacetate, sodium chloride, potassium chloride, calcium chloride, sodiumlactate and the like. The concentration of antibody or antigen bindingfragment or conjugate in these formulations can vary widely, and will beselected primarily based on fluid volumes, viscosities, body weight andthe like in accordance with the particular mode of administrationselected and the subject's needs. Actual methods of preparing suchdosage forms are known, or will be apparent, to those skilled in theart.

A typical composition for intravenous administration includes about 0.01to about 30 mg/kg of antibody or antigen binding fragment or conjugateper subject per day (or the corresponding dose of a conjugate includingthe antibody or antigen binding fragment). Actual methods for preparingadministrable compositions will be known or apparent to those skilled inthe art and are described in more detail in such publications asRemington's Pharmaceutical Science, 19th ed., Mack Publishing Company,Easton, Pa. (1995). In some embodiments, the composition can be a liquidformulation including one or more antibodies, antigen binding fragments(such as an antibody or antigen binding fragment that specifically bindsto TEM8), in a concentration range from about 0.1 mg/ml to about 20mg/ml, or from about 0.5 mg/ml to about 20 mg/ml, or from about 1 mg/mlto about 20 mg/ml, or from about 0.1 mg/ml to about 10 mg/ml, or fromabout 0.5 mg/ml to about 10 mg/ml, or from about 1 mg/ml to about 10mg/ml.

Antibodies, antigen binding fragments, or conjugates may be provided inlyophilized form and rehydrated with sterile water beforeadministration, although they are also provided in sterile solutions ofknown concentration. The antibody or antigen binding fragment orconjugate solution is then added to an infusion bag containing 0.9%sodium chloride, USP, and in some cases administered at a dosage of from0.5 to 15 mg/kg of body weight. Considerable experience is available inthe art in the administration of antibody or antigen binding fragmentand conjugate drugs; for example, antibody drugs have been marketed inthe U.S. since the approval of RITUXAN® in 1997. Antibodies, antigenbinding fragments and conjugates can be administered by slow infusion,rather than in an intravenous push or bolus. In one example, a higherloading dose is administered, with subsequent, maintenance doses beingadministered at a lower level. For example, an initial loading dose of 4mg/kg antibody or antigen binding fragment (or the corresponding dose ofa conjugate including the antibody or antigen binding fragment) may beinfused over a period of some 90 minutes, followed by weekly maintenancedoses for 4-8 weeks of 2 mg/kg infused over a 30 minute period if theprevious dose was well tolerated.

Controlled release parenteral formulations can be made as implants, oilyinjections, or as particulate systems. For a broad overview of proteindelivery systems see, Banga, A. J., Therapeutic Peptides and Proteins:Formulation, Processing, and Delivery Systems, Technomic PublishingCompany, Inc., Lancaster, Pa., (1995). Particulate systems includemicrospheres, microparticles, microcapsules, nanocapsules, nanospheres,and nanoparticles. Microcapsules contain the therapeutic protein, suchas a cytotoxin or a drug, as a central core. In microspheres thetherapeutic is dispersed throughout the particle. Particles,microspheres, and microcapsules smaller than about 1 μm are generallyreferred to as nanoparticles, nanospheres, and nanocapsules,respectively. Capillaries have a diameter of approximately 5 μm so thatonly nanoparticles are administered intravenously. Microparticles aretypically around 100 μm in diameter and are administered subcutaneouslyor intramuscularly. See, for example, Kreuter, J., Colloidal DrugDelivery Systems, J. Kreuter, ed., Marcel Dekker, Inc., New York, N.Y.,pp. 219-342 (1994); and Tice & Tabibi, Treatise on Controlled DrugDelivery, A. Kydonieus, ed., Marcel Dekker, Inc. New York, N.Y., pp.315-339, (1992).

Polymers can be used for ion-controlled release of the antibody orantigen binding fragment or conjugate compositions disclosed herein.Various degradable and nondegradable polymeric matrices for use incontrolled drug delivery are known in the art (Langer, Accounts Chem.Res. 26:537-542, 1993). For example, the block copolymer, polaxamer 407,exists as a viscous yet mobile liquid at low temperatures but forms asemisolid gel at body temperature. It has been shown to be an effectivevehicle for formulation and sustained delivery of recombinantinterleukin-2 and urease (Johnston et al., Pharm. Res. 9:425-434, 1992;and Pec et al., J. Parent. Sci. Tech. 44(2):58-65, 1990). Alternatively,hydroxyapatite has been used as a microcarrier for controlled release ofproteins (Ijntema et al., Int. J. Pharm. 112:215-224, 1994). In yetanother aspect, liposomes are used for controlled release as well asdrug targeting of the lipid-capsulated drug (Betageri et al., LiposomeDrug Delivery Systems, Technomic Publishing Co., Inc., Lancaster, Pa.(1993)). Numerous additional systems for controlled delivery oftherapeutic proteins are known (see U.S. Pat. No. 5,055,303; U.S. Pat.No. 5,188,837; U.S. Pat. No. 4,235,871; U.S. Pat. No. 4,501,728; U.S.Pat. No. 4,837,028; U.S. Pat. No. 4,957,735; U.S. Pat. No. 5,019,369;U.S. Pat. No. 5,055,303; U.S. Pat. No. 5,514,670; U.S. Pat. No.5,413,797; U.S. Pat. No. 5,268,164; U.S. Pat. No. 5,004,697; U.S. Pat.No. 4,902,505; U.S. Pat. No. 5,506,206; U.S. Pat. No. 5,271,961; U.S.Pat. No. 5,254,342 and U.S. Pat. No. 5,534,496).

In some examples, a subject is administered the DNA encoding theantibody or antigen binding fragments thereof, to provide in vivoantibody production, for example using the cellular machinery of thesubject. Immunization by nucleic acid constructs is well known in theart and taught, for example, in U.S. Pat. No. 5,643,578, and U.S. Pat.No. 5,593,972 and U.S. Pat. No. 5,817,637. U.S. Pat. No. 5,880,103describes several methods of delivery of nucleic acids encoding to anorganism. The methods include liposomal delivery of the nucleic acids.Such methods can be applied to the production of an antibody, orantibody binding fragments thereof, by one of ordinary skill in the art.

One approach to administration of nucleic acids is direct administrationwith plasmid DNA, such as with a mammalian expression plasmid. Thenucleotide sequence encoding the disclosed antibody, or antibody bindingfragments thereof, can be placed under the control of a promoter toincrease expression.

In another approach to using nucleic acids, a disclosed antibody, orantibody binding fragments thereof can also be expressed by attenuatedviral hosts or vectors or bacterial vectors. Recombinant vaccinia virus,adeno-associated virus (AAV), herpes virus, retrovirus, cytomegalovirusor other viral vectors can be used to express the antibody. For example,vaccinia vectors and methods useful protocols are described in U.S. Pat.No. 4,722,848. BCG (Bacillus Calmette Guerin) provides another vectorfor expression of the disclosed antibodies (see Stover, Nature351:456-460, 1991).

In one embodiment, a nucleic acid encoding a disclosed antibody, orantibody binding fragments thereof, is introduced directly into cells.For example, the nucleic acid can be loaded onto gold microspheres bystandard methods and introduced into the skin by a device such asBio-Rad's HELIOS™ Gene Gun. The nucleic acids can be “naked,” consistingof plasmids under control of a strong promoter.

Typically, the DNA is injected into muscle, although it can also beinjected directly into other sites. Dosages for injection are usuallyaround 0.5 μg/kg to about 50 mg/kg, and typically are about 0.005 mg/kgto about 5 mg/kg (see, e.g., U.S. Pat. No. 5,589,466).

H. Kits

Kits are also provided. For example, kits for detecting a cell (such asan endothelial cell or a pericytes) that expresses TEM8 in a subject,treating a tumor in a subject, or decreasing binding of Anthrax PA to acell. The kits will typically include an antibody or antigen bindingfragment that specifically binds TEM8 and/or a conjugate thereof.

More than one of the conjugates or antibodies or antigen bindingfragments that specifically bind TEM8 can be included in the kit. Thus,the kit can include two or more antibodies that specifically bind TEM8,or an antibody or antigen binding fragment that specifically binds TEM8and a conjugate thereof, or a combination thereof. In some embodiments,an antigen binding fragment or conjugate including an antigen bindingfragment, such as an Fv fragment, is included in the kit. In oneexample, such as for in vivo uses, the antibody can be a scFv fragment.

The kit can include a container and a label or package insert on orassociated with the container. Suitable containers include, for example,bottles, vials, syringes, etc. The containers may be formed from avariety of materials such as glass or plastic. The container typicallyholds a composition including one or more of the disclosed TEM8 specificantibodies, antigen binding fragments, or conjugates. In severalembodiments the container may have a sterile access port (for examplethe container may be an intravenous solution bag or a vial having astopper pierceable by a hypodermic injection needle). A label or packageinsert indicates that the composition is used for treating theparticular condition.

The label or package insert typically will further include instructionsfor use of a disclosed TEM8 specific antibodies or fragments thereof, orconjugates thereof, for example, in a method of treating or preventing atumor. The package insert typically includes instructions customarilyincluded in commercial packages of therapeutic products that containinformation about the indications, usage, dosage, administration,contraindications and/or warnings concerning the use of such therapeuticproducts. The instructional materials may be written, in an electronicform (such as a computer diskette or compact disk) or may be visual(such as video files). The kits may also include additional componentsto facilitate the particular application for which the kit is designed.Thus, for example, the kit may additionally contain means of detecting alabel (such as enzyme substrates for enzymatic labels, filter sets todetect fluorescent labels, appropriate secondary labels such as asecondary antibody, or the like). The kits may additionally includebuffers and other reagents routinely used for the practice of aparticular method. Such kits and appropriate contents are well known tothose of skill in the art.

EXAMPLES

The following examples are provided to illustrate particular features ofcertain embodiments, but the scope of the claims should not be limitedto those features exemplified.

Example 1 TEM8 Specific Antibodies

This example illustrates the isolation of a panel of fully humananti-TEM8 antibodies from a human naïve yeast display scFv library, andcharacterization of those antibodies. The selection strategy involvedserial panning of the libraries on both TEM8-transfected mammalian cellsand purified recombinant TEM8-ED protein derived from mammalian cells,and resulted in the identification of four TEM8 antibodies, termed m825,m822, m830, and m863.

Four fully human monoclonal antibodies, m822, m825, m830 and m863 wereidentified from a human naïve yeast display scFv library by sorting,screening and affinity maturation against human and mouse TEM8. The TEM8antibodies were identified from a library screen (see Puri et al., MAbs.5:533-9, 2013 for a description of the library). The sequences of theheavy and light chain variable regions, as well as the heavy and lightchain CDRs (defined by IMGT) of the identified antibodies are providedin Table 3, below.

Recombinant human and mouse TEM8 ectodomain proteins were used as thetarget for selection. In the first round of selection, approximately5×10¹⁰ cells from the naïve antibody library were incubated with 10 μgof biotinylated human TEM8 protein in 50 ml 0.1% bovine serum albumin(BSA)-phosphate-buffered saline (PBS), called PBSA, at room temperaturefor 2 hours with gentle rotation. Then, the mixture was washed threetimes with 0.1% PBSA to remove the unbound antibody fragments.Biotinylated TEM8 together with bound antibody fragments weresubsequently incubated with 100 μl of strepatavidin-conjugatedmicrobeads (Milenvi Biotec, Auburn, Calif.) and loaded onto the AutoMACSsystem for sorting. Cells which display antibody fragments with highaffinity to TEM8 were collected and later amplified in SDCAA Medium (20g Dextrose, 6.7 g Difco yeast nitrogen base without amino acids, 5 gBacto casamino acids, 5.4 g Na₂HPO₄ and 8.56 g NaH₂PO₄. H₂O dissolved in1 L of distilled water) at 250 rpm at 30° C. for 24 hours. After that,the culture was induced in SGCAA Medium (20 g Galactose, 20 g Raffinose,1 g Dextrose, 6.7 g Difco yeast nitrogen base without amino acids, 5 gBacto casamino acids, 5.4 g Na₂HPO₄ and 8.56 g NaH₂PO₄. H₂O dissolved in1 L of distilled water) at 250 rpm at 20° C. for 18 hours. The poolobtained was subjected to another round of selection for binding tobiotinylated recombinant human TEM8. To ensure sufficient diversity ofantibody fragments for second and third rounds of screening, 100 foldsof the pool size from the prior round of sorting was used as the inputcell number.

For the third round of selection, Fc-fused recombinant human TEM8 wasused. The screening was carried out in a similar way to the previous tworounds of selection toward human TEM8. Finally, antibody fragments thatbound to human TEM8 were pulled down by protein G-conjugated microbeads.The yeast cells expressing antibody fragments that possess high bindingaffinity to human TEM8 were collected and further characterized.

TABLE 3 Protein sequence of the VH and VL domains of the m825, m822, m830, and m863 antibodies (with IMGT CDRs in bold). Anti-body protein sequence (CDRs underlined) m825 VH QVQLVQSGAEVKKPGTSVKVSCKVPGYTFSSYAISWVRQAPGQGLEWMGGIIPIFGTTNYAQKFQGRVTITGEESTSTVYMELSSLRSEDTAVYYCARDTDYMFDYWGQGTLVTVSS  (SEQ ID NO: 1) VL SSELTQDPVVSVALGETVSITCQGDNLRDFYASWYQQKPGQAPLLVMYGKNRRPSGIPDRFSGSTSGNTLSLTITGAQ AEDEADYYCSSRDNSKHVVFGGGTKVTVL (SEQ ID NO: 2) m822 VH  QVQLVQSGAEVKKPGASVKVSCKVSGYTFSSYAISWVRQAPGQGLEWMGGIIPIFGTANYAQKFQGRVTITADESTSTAYMELSSLRSEDTAVYYCARDTDYMFDYWGQGTLVTVSS  (SEQ ID NO: 3) VL SSELTQDPVVSVALGETVSITCQGDNLRDFYASWYQQKPGQAPLLVMYGKNRRPSGIPDRFSGSTSGNTLSLTITGAQ AEDEADYYCSSRDNSKHVVFGGGTKVTVL(SEQ ID NO: 4) m830 VH  EVQLVESGGGVVQPGRSVRLSCAASGFTFSTYTMHWVRQAPGKGLEWVAIISNDGSNKYYADPVRGRFTISRDNSKNTLYLQMNSLRAEDTAVYYCVRGSSWYRGNWFDPWGQGTLV  TVSS (SEQ ID NO: 5) VL DIQMTQSPSSLSASVGDRVTIACRASQTISRYLNWYQQKPGKAPKLLIYAASSLQSGVSSRFSGSGSGTEFTLTISSL QPEDFATYFCQQTYSPPITFGQGTRLEIKR (SEQ ID NO: 6) m863 VH  EVQLVETGAEVKKPGASVKVSCKASGYTFTGYYMHWVRQAPGQGLEWMGWINPTSGSTNYAQKFQGRVTMTRDTSISTAYMELSGLRSDDTAVYYCVRDPGSPKWLAFDPWGQGTLV  TVSS (SEQ ID NO: 7) VL DIQLTQSPSSLSASVGDRVTITCRASRAISRYLNWYQQKPGKAPKLLIYAASSLQSGVSSRFSGSGSGTEFTLTISSL QPEDFATYFCQQTYSPPITFGQGTRLEIKR (SEQ ID NO: 8)

The binding affinity of the m822, m825, m830, and m863 antibodyinteraction with TEM8 was assayed by surface plasmon resonance. Theassay was performed on a Biacore instrument substantially as described(see, e.g., Feng et al., Mol Cancer Ther. 2006 January; 5(1):114-20.)using a for the m822, m825, m830, and m863 antibodies in IgG1 format andrecombinant human TEM8 ectodomain. The apparent K_(D) for m822, m825,m830, and m863 antibody binding to TEM8 determined by these assays ispresented in Table 4.

TABLE 4 Binding affinities of the TEM8 antibodies measured by surfaceplasmon resonance Antibody Calculated K_(D) (M) m822 3.5 × 10⁻⁸ m825 3.4× 10⁻¹¹ m830 1.2 × 10⁻⁸ m863 1.2 × 10⁻⁹

The m825, m822, m830, and m863 were converted to human IgG according tostandard methods (see, e.g., Zhu et al., J Virol. 2006 January;80(2):891-9).

Screening assays were performed using the m825, m822, m830, and m863antibodies in human IgG1 format to confirm that these antibodies canbind with high affinity to both human and mouse TEM8 in soluble form andalso the cell surface native forms, but not human or mouse CMG2, asecond receptor for anthrax toxin protein (ANTXR2). The screening assayswere performed substantially as described in Chaudhary et al., CancerCell, 21:212-226, 2012, and PCT Pub. Nos. WO2012174160, each of which isincorporated herein in its entirety. Briefly, Chinese hamster ovary(CHO) cells or human embryonic kidney 293 (293) cells expressing humanTEM8 (hTEM8) or human CMG2 (hCMG2) were incubated with the m825, m822,m830, or m863 antibody and binding was assayed using FACS analysis. Theresults show that each of the m825, m822, m830, and m863 antibodiesbound to hTEM8 on the cell surface, but not to hCMG2 (see FIGS. 1A and1B).

The m825, m822, m830, and m863 antibodies were also tested to determineif they can inhibit the binding of protective antigen (PA) subunit ofanthrax toxin to TEM8 according to previously described methods(Chaudhary et al., Cancer Cell, 21:212-226, 2012, and PCT Pub. Nos.WO2012174160, each of which is incorporated herein in its entirety).Each of the m825, m822, m830, and m863 antibodies inhibited (PA) bindingto TEM8.

The m825, m822, m830, and m863 antibodies were also tested to determineif they can be used to label tumor vessels. Immunofluorescence stainingassays were performed to determine if the m825 antibody in human IgGformat (human m825-IgG1) would specifically label tumor blood vessels(FIG. 2). The assays were performed substantially as previouslydescribed (Chaudhary et al., Cancer Cell, 21:212-226, 2012, and PCT Pub.Nos. WO2012174160, each of which is incorporated herein in itsentirety). Briefly, wildtype (WT) and TEM8 knockout TEM8 KO mice wereadministered DLD-1 cells subcutaneously and a xenograft tumor wasallowed to develop. A sample from the tumor was obtained and stainedwith CD31 antibody (specific for blood vessels) and the human m825-IgG1antibody. As illustrated in FIG. 2, the human m825-IgG1 specificallystained tumor vessels. This result indicates that the identified TEM8antibodies can be used as diagnostic reagents for detections of tumorblood vessels.

Animal studies were performed to demonstrate that the antibodies inhibittumor growth in vivo.

First, the human m825-IgG1 antibody was assayed for inhibition of UACCmelanoma cell xenografts grown subcutaneously in athymic nude mice. Theassay method used was substantially according to previously describedmethods (Chaudhary et al., Cancer Cell, 21:212-226, 2012, and PCT Pub.Nos. WO2012174160, each of which is incorporated herein in itsentirety). Briefly, human m825-IgG1 antibody, control IgG, or controlvehicle (PBS), were administered IP to the mice at a dose of 20 or 40mg/kg starting 7 days after inoculation of the mice with the UACC cells(see arrows indicating treatment days in FIG. 3). Treatment with humanm825-IgG1 significantly reduced tumor volume over the course of theexperiment compared to controls (FIG. 3).

Additionally, human m825-IgG1 was assayed for inhibition of HCT-116colon cancer cell xenografts grown subcutaneously in athymic nude mice.The assay method used was performed substantially according topreviously described methods (Chaudhary et al., Cancer Cell, 21:212-226,2012, and PCT Pub. Nos. WO2012174160, each of which is incorporatedherein in its entirety). Briefly, human m825-IgG1 antibody, control IgG,or control vehicle (PBS), were administered IP to the mice at a dose of15 mg/kg on after inoculation of the mice with the HCT-116 cells (seearrows indicating treatment days in FIG. 4). Treatment with humanm825-IgG1 significantly reduced tumor volume over the course of theexperiment compared to controls (FIG. 4).

Further, the m825, m822, m830, and m863 antibodies in human IgG formatwere each assayed for inhibition of UACC melanoma cell xenografts grownsubcutaneously in athymic nude mice (FIG. 5). The assay method used wassubstantially according to previously described methods (Chaudhary etal., Cancer Cell, 21:212-226, 2012, and PCT Pub. Nos. WO2012174160, eachof which is incorporated herein in its entirety). Briefly, m825, m822,m830, or m863 antibody, or control vehicle (PBS), was administered IP tothe mice at a dose of 15 mg/kg on the seventh day after inoculation ofthe mice with the UACC cells. Treatment with the m825, m822, m830, andm863 antibodies significantly reduced tumor volume over the course ofthe experiment compared to controls (FIG. 5).

Additionally, assays were performed to determine if the anti-TEM8antibodies could inhibit tumor metastasis in an animal model (FIG. 6).Athymic nude mice were injected intrasplenically with human colon cancercells. The mice were then treated with the human m830-IgG1 antibody, andmetastasis of the colon cancer to the liver of the mice was measuredusing bioluminescence. As shown in FIGS. 6 A and 6B, treatment with thehuman m830-IgG1 antibody drastically reduced metastasis in this animalmodel.

An antibody drug conjugate including the m825 antibody (in human IgG1format) conjugated to MMAE (m825-MMAE) was generated substantiallyaccording to previously described methods (see, e.g., U.S. Pub. Nos.2011/0268751, 2008/0305044, 2007/0258987, each of which is incorporatedby reference herein in its entirety). Briefly, inter-chain disulfidebonds of purified m825 antibody were partially reduced with tris(2-carboxyethyl)-phosphine hydrochloride (TCEP HCL) to form thiolgroups. The reaction was performed at 25° C. for 1.5 hours with a TCEPconcentration of 2.2 mole equivalents to m825 antibody. The partiallyreduced m825 antibody was incubated with MMAE toxin linked to astretcher unit, a Val-Cit peptide cleavage site, and a spacer set forthas:

The reaction was performed at 25° C. for 1 hour with the MMAE compoundconcentration of 5.5 mole equivalents to m825 antibody. DMSO wasincluded in the reaction at 10.5% v/v to maintain solubility of the MMAElinker. The conjugation reaction was then quenched by adding a 10× molarration of N-Acetyl-L-Cysteine relative to m825 antibody at 25° C. for 15minutes. The resulting m825-MMAE conjugate was subjected to bufferexchange using standard methods, and concentrated as needed.

The m825-MMAE conjugate was tested for binding to cell-surface TEM8 byassaying binding to CHO cells expressing human TEM8. As shown in FIG. 7,the m825-MMAE conjugate specifically bound to the TEM8 expressing CHOcells, but not to control CHO cells lacking TEM8 expression.

The selectivity of the m825-MMAE conjugate for TEM8 expressing cells wasassayed in vitro (FIG. 8). HEK 293 cells (control) or HEK 293 cellsexpressing TEM8 were treated with MMAE alone, human m825-IgG1 antibody,or the m825-MMAE conjugate. As shown in FIG. 8, the MMAE toxin alone wascytotoxic towards HEK 293 cells regardless of TEM8 expression, whereasthe m825-MMAE conjugate was only cytotoxic toward HEK-293 cellsexpressing TEM8.

To further assay the anti-cancer activity of anti-TEM8 antibodies andantibody-drug conjugates thereof, the effects of these compounds onxenograft growth in Athymic nude mice was tested (FIGS. 9 and 10). Humancolon cancer xenografts (HCT116 cells) were grown subcutaneously inAthymic nude mice. The mice were treated with the m825-MMAE conjugate ata concentration of 1, 3, 10, or 30 mg/kg, or human m825-IgG1 antibodyalone at a concentration of 10 or 30 mg/kg, twice a week for threeweeks. The results indicate that both the human m825-IgG1 antibody andthe m825-MMAE conjugate successfully reduced tumor growth in this animalmodel. Additionally, at comparable dosages, the m825-MMAE conjugate wasmore effective at reducing tumor growth that m825 antibody alone.

Additionally, ovarian cancer xenografts (OVCAR3 cells) were grownsubcutaneously in Athymic nude mice. The mice were treated with them825-MMAE conjugate (1, 3, or 10 mg/kg), human m825-IgG1 antibody alone(10 mg/kg), or MMAE alone (0.2 mg/kg), twice a week for three and a halfweeks. The results show that the m825-MMAE conjugate (at 3 and 10 mg/kg)reduced xenograft growth in this animal model. Additionally, atcomparable dosages, the m825-MMAE conjugate was more effective atreducing tumor growth that m825 antibody alone.

These in vivo assays illustrate that the m825, m822, m830, and m863antibodies, and antibody-drug-conjugates thereof, can be used as cancertherapeutics.

Example 2 Detection of an Endothelial Cell that Expresses TEM8 in aHuman

This example describes particular methods that can be used to detect anendothelial cell that expresses TEM8 in a subject. However, one skilledin the art will appreciate that similar methods can be used. Suchdetection may be performed, for example, before, during, or after,treating the subject (or combination thereof) with an antibody thatspecifically binds TEM8 or conjugate thereof.

A TEM8 specific monoclonal antibody (such, but not limited to, a TEM8specific monoclonal antibody including a heavy chain variable regionincluding a H-CDR1, H-CDR2, and H-CDR3 including amino acids 26-33,51-58, and 97-106 of SEQ ID NO: 1, respectively, and a light chainvariable region including a L-CDR1, L-CDR2, and L-CDR3 including aminoacids 26-31, 49-51, and 88-97 of SEQ ID NO: 2, respectively) or a TEM8specific monoclonal antibody conjugated to a detectable marker isadministered to the subject. Administration can be achieved by anysufficient method known in the art, but is typically intravenousadministration. Typically, the conjugate is administered as a componentof a composition including the conjugate and a pharmaceuticallyacceptable carrier.

An effective amount of the antibody or conjugate is administered to thesubject. The amount of antibody or conjugate administered is sufficientto form a detectable immune complex with TEM8 in the subject. Aeffective amount can being readily determined by one skilled in the art,for example using routine trials establishing dose response curves. Inaddition, particular exemplary dosages are provided above. The antibodyor conjugate can be administered in single or multiple dose delivery orvia continuous delivery over an extended time period.

In the case of an antibody, the antibody utilized for detection ofpathological angiogenesis in a subject is detected with a secondaryreagent (such as a secondary antibody conjugated to a detectable marker)useful for diagnostic imaging. For example, a detectable marker used formagnetic resonance imaging, such as super paramagnetic iron oxidenanocrystals. The particular secondary reagent will depend on theparticular type of diagnostic imaging utilizes, as will be appreciatedby the skilled artisan.

In the case of a conjugate, the conjugate utilized for detection ofpathological angiogenesis in a subject typically includes a detectablemarker useful for diagnostic imaging. For example, a detectable markerused for magnetic resonance imaging, such as super paramagnetic ironoxide nanocrystals. The particular detectable marker will depend on theparticular type of diagnostic imaging utilizes, as will be appreciatedby the skilled artisan.

Detection of the endothelial cell that expresses TEM8 is accomplished bydetecting the antibody or conjugate immobilized in the subject using thediagnostic imaging method corresponding to the detectable marker used.For example, if the detectable marker is super paramagnetic iron oxidenanocrystals, then the diagnostic imaging methods will typically includemagnetic resonance imaging.

Example 3 Treatment of Cancer in a Human

This example describes a particular method that can be used to treat aprimary or metastatic tumor in humans by administration of one or moreantibodies that specifically bind TEM8 or a conjugate thereof. Althoughparticular methods, dosages, and modes of administrations are provided,one skilled in the art will appreciate that variations can be madewithout substantially affecting the treatment.

Human patients are treated intravenously with at least 1 μg (such as0.001-1000 mg) of one or more antibodies that specifically bind TEM8 orconjugate thereof, (such, but not limited to, a TEM8 specific monoclonalantibody including a heavy chain variable region including a H-CDR1,H-CDR2, and H-CDR3 including amino acids 26-33, 51-58, and 97-106 of SEQID NO: 1, respectively, and a light chain variable region including aL-CDR1, L-CDR2, and L-CDR3 including amino acids 26-31, 49-51, and 88-97of SEQ ID NO: 2, respectively), for example for a period of at least 1day, 1 week, 1 month, at least 2 months, at least 3 months, at least 6months, at least one year, at least 2 years, or at least five years ormore or less time. Administration of the antibody or conjugate can beused in conjunction with normal cancer therapy (for example rather thanreplacing the therapy). Thus, the antibody or conjugate can be added tothe usual and customary anti-angiogenic, chemotherapy, surgery,radiation treatments (or combination thereof) conventionally used forthe particular tumor type. Administration of the antibody or conjugatecan be continued after customary therapy was stopped and can be takenlong term (for example over a period of months or years).

Briefly, the method includes screening subjects to determine if theyhave a tumor, such as a primary or metastatic tumor. Subjects having atumor are selected. In a clinical trial, half of the subjects wouldfollow the established protocol for treatment of the tumor (such as anormal anti-angiogenic/chemotherapy/radiotherapy/surgery regimen). Theother half would follow the established protocol for treatment of thetumor (such as a normalanti-angiogenic/chemotherapy/radiotherapy/surgery regimen) incombination with administration of the a antibody or conjugate describedherein. In some examples, the tumor is surgically excised (in whole orpart) prior to treatment with the antibody or conjugate.

Screening Subjects

The subject is first screened to determine if they have a tumor.Examples of methods that can be used to screen for tumors include acombination of ultrasound, tissue biopsy, or detection oftumor-associated vasculature. However, such pre-screening is notrequired prior to administration of the antibody or conjugate disclosedherein.

Pre-Treatment of Subjects

The subject is treated prior to administration of an antibody thatspecifically binds TEM8 or conjugate thereof. However, suchpre-treatment is not always required, as can be determined by a skilledclinician. For example, the tumor can be surgically excised (in total orin part) prior to administration of one or more antibodies orconjugates. In addition, the subject can be treated with an establishedprotocol for treatment of the particular tumor present (such as a normalanti-angiogenesis/chemotherapy/radiotherapy regimen).

Administration

Administration can be achieved by any sufficient method known in theart, but is typically intravenous administration. Typically, theantibody or conjugate is administered as a component of a compositionincluding the antibody or conjugate and a pharmaceutically acceptablecarrier.

A therapeutically effective amount of the antibody or conjugate isadministered to the subject. The amount of antibody or conjugateadministered is sufficient to treat a subject having a tumor. Atherapeutically effective amount can be readily determined by oneskilled in the art, for example using routine trials establishing doseresponse curves. In addition, particular exemplary dosages are providedabove. The antibody or conjugate can be administered in a single dosedelivery, via continuous delivery over an extended time period, in arepeated administration protocol (for example, by a daily, weekly, ormonthly repeated administration protocol).

Assessment

Following the administration of one or more therapies, subjects having atumor can be monitored for tumor treatment, such as regression orreduction in tumor burden (for example, reduction in metastaticlesions). In particular examples, subjects are analyzed one or moretimes, starting seven days following treatment.

Subjects can be monitored using any method known in the art. Forexample, diagnostic imaging can be used (such as x-rays, CT scans, MRIs,ultrasound, fiber optic examination, and laparoscopic examination), aswell as analysis of biological samples from the subject (for exampleanalysis of blood, tissue biopsy, or other biological samples), such asanalysis of the type of cells present, or analysis for a particulartumor marker. In one example, if the subject has a metastatic tumor,assessment can be made using ultrasound, MRI, or CAT scans and analysisof the type of cells contained in a tissue biopsy.

In view of the many possible embodiments to which the principles of thedisclosed embodiments may be applied, it should be recognized that theillustrated embodiments are only preferred examples of the invention andshould not be taken as limiting. We therefore claim all that comeswithin the scope and spirit of the following claims.

We claim:
 1. An isolated monoclonal antibody or antigen binding fragmentthereof, comprising a heavy chain variable region and a light chainvariable region, comprising one of: (a) a heavy chain complementaritydetermining region (H-CDR)1, a H-CDR2, and a H-CDR3 of the heavy chainvariable region set forth as SEQ ID NO: 1, and a light chaincomplementarity determining region (L-CDR)1, a L-CDR2, and a L-CDR3 ofthe light chain variable region set forth as SEQ ID NO: 2 (m825); (b) aH-CDR1, a H-CDR2, and a H-CDR3 of the heavy chain variable region setforth as SEQ ID NO: 3, and a L-CDR1, a L-CDR2, and a L-CDR3 of the lightchain variable region set forth as SEQ ID NO: 4 (m822); (c) a H-CDR1, aH-CDR2, and a H-CDR3 of the heavy chain variable region set forth as SEQID NO: 5, and a L-CDR1, a L-CDR2, and a L-CDR3 of the light chainvariable region set forth as SEQ ID NO: 6 (m830); or (d) a H-CDR1, aH-CDR2, and a H-CDR3 of the heavy chain variable region set forth as SEQID NO: 7, and a L-CDR1, a L-CDR2, and a L-CDR3 of the light chainvariable region set forth as SEQ ID NO: 8 (m863); and wherein themonoclonal antibody or antigen binding fragment specifically binds totumor endothelial marker 8 (TEM8) and is neutralizing.
 2. The antibodyor antigen binding fragment of claim 1, wherein: (a) the H-CDR1, H-CDR2,and H-CDR3, comprise amino acids 26-33, 51-58, and 97-106 of SEQ ID NO:1, respectively, and the L-CDR1, L-CDR2, and L-CDR3 comprise amino acids26-31, 49-51, and 88-97 of SEQ ID NO: 2, respectively (m825); (b) theH-CDR1, H-CDR2, and H-CDR3, comprise amino acids 26-33, 51-58, and97-106 of SEQ ID NO: 3, respectively, and the L-CDR1, L-CDR2, and L-CDR3comprise amino acids 26-31, 49-51, and 88-97 of SEQ ID NO: 4,respectively (m822); (c) the H-CDR1, H-CDR2, and H-CDR3, comprise aminoacids 26-33, 51-58, and 97-110 of SEQ ID NO: 5, respectively, and theL-CDR1, L-CDR2, and L-CDR3 comprise amino acids 27-32, 50-52, and 89-97of SEQ ID NO: 6, respectively (m830); or (d) the H-CDR1, H-CDR2, andH-CDR3, comprise amino acids 26-33, 51-58, and 97-110 of SEQ ID NO: 7,respectively, and the L-CDR1, L-CDR2, and L-CDR3 comprise amino acids27-32, 50-52, and 89-97 of SEQ ID NO: 8, respectively (m863).
 3. Theantibody or antigen binding fragment of claim 1, comprising: (a),wherein the heavy chain variable region comprises the amino acidsequence set forth as SEQ ID NO: 1; (b), wherein the heavy chainvariable region comprises the amino acid sequence set forth as SEQ IDNO: 3; (c), wherein the heavy chain variable region comprises the aminoacid sequence set forth as SEQ ID NO: 5; or (d), wherein the heavy chainvariable region comprises the amino acid sequence set forth as SEQ IDNO:
 7. 4. The antibody or antigen binding fragment of claim 1,comprising: (a), wherein the light chain variable region comprises theamino acid sequence set forth as SEQ ID NO: 2; (b), wherein the lightchain variable region comprises the amino acid sequence set forth as SEQID NO: 4; (c), wherein the light chain variable region comprises theamino acid sequence set forth as SEQ ID NO: 6; or (d), wherein the lightchain variable region comprises the amino acid sequence set forth as SEQID NO:
 8. 5. The antibody or antigen binding fragment of claim 1,wherein the heavy and light chain variable regions comprise the aminoacid sequences set forth as (a) SEQ ID NO: 1 and SEQ ID NO: 2,respectively; (b) SEQ ID NO: 3 and SEQ ID NO: 4, respectively; (c) SEQID NO: 5 and SEQ ID NO: 6, respectively; or (d) SEQ ID NO: 7 and SEQ IDNO: 8, respectively.
 6. The antibody of claim 1, wherein the monoclonalantibody or antigen binding fragment comprises a human framework region.7. The antibody of claim 1, wherein the antibody is an IgG.
 8. Theantibody of claim
 1. 9. The antigen binding fragment of claim
 1. 10. Theantigen binding fragment of claim 9, wherein the antigen bindingfragment is a Fv, Fab, F(ab′)₂, scFV or a scFV₂ fragment.
 11. Theantibody or antigen binding fragment of claim 1, conjugated to aneffector molecule or a detectable marker.
 12. The antibody or antigenbinding fragment of claim 11, wherein the effector molecule is ananti-angiogenic agent, chemotherapeutic agent, and/or toxin.
 13. Theantibody or antigen binding fragment of claim 12, wherein the toxin is amaytansinoid toxin and/or an auristatin toxin.
 14. The isolatedmonoclonal antibody or antigen binding fragment of claim 13, wherein themaytansinoid toxin is DM1; and/or the auristatin toxin is MonomethylAuristatin E (MMAE) or Monomethyl Auristatin F (MMAF).
 15. The antibodyor antigen binding fragment of claim 11, wherein the antibody or antigenbinding fragment is conjugated to the effector molecule by a linker. 16.The antibody or antigen binding fragment of claim 15, wherein the linkeris a cleavable linker.
 17. The antibody or antigen binding fragment ofclaim 16, wherein the linker is a cathepsin-cleavable linker.
 18. Theantibody or antigen binding fragment of claim 15, wherein the linker isa selectively cleavable peptide linker.
 19. The antibody or antigenbinding fragment of claim 15, wherein the linker is a non-cleavablelinker.
 20. The antibody or antigen binding fragment of claim 11,wherein the detectable marker is a fluorescent, enzymatic, heavy metalor radioactive marker.
 21. An isolated nucleic acid molecule encodingthe antibody or antigen binding fragment of claim
 1. 22. The nucleicacid molecule of claim 21, encoding a chimeric antigen receptor.
 23. Avector comprising the nucleic acid molecule of claim
 21. 24. The vectorof claim 23, for use in making a chimeric antigen receptor T cell.
 25. Ahost cell, comprising the nucleic acid molecule of claim 21 or a vectorcomprising the nucleic acid molecule.
 26. The host cell of claim 25,wherein the host cell is a T cell.
 27. An antibody-drug-conjugateaccording to formula I:

wherein A is an antibody or antigen binding fragment thereof comprisinga heavy chain variable region comprising a heavy chain complementaritydetermining region (H-CDR)1, a H-CDR2, and a H-CDR3 comprising aminoacids 26-33, 51-58, and 97-106 of SEQ ID NO: 1, respectively, and alight chain variable region comprising a light chain complementaritydetermining region (L-CDR)1, a L-CDR2, and a L-CDR3 comprising aminoacids 26-31, 49-51, and 88-97 of SEQ ID NO: 2, respectively, wherein theantibody or antigen binding fragment specifically binds to tumorendothelial marker 8 (TEM 8); wherein S is a sulfur atom of theantibody; and wherein n is an integer between 1 and
 10. 28. The antibodydrug conjugate of claim 27, wherein the heavy chain variable regioncomprises the amino acid sequence set forth as SEQ ID NO: 1 and thelight chain variable region comprises the amino acid sequence set forthas SEQ ID NO:
 2. 29. The antibody drug conjugate of claim 27, wherein nis an even integer from 2 to
 8. 30. The antibody drug conjugate of claim27, wherein n is an even integer from 2 to
 4. 31. A composition,comprising an effective amount of the antibody or antigen bindingfragment of claim 1, a nucleic acid molecule encoding the antibody orantigen binding fragment, or an antibody drug conjugate comprising theantibody or antigen binding fragment, and a pharmaceutically acceptablecarrier.
 32. A kit for detecting pathological angiogenesis in a subject,treating a tumor in a subject, or decreasing the binding of Anthraxprotective antigen to a cell, comprising a container comprising theantibody or antigen binding fragment of claim 1, or a nucleic acidmolecule encoding the antibody or antigen binding fragment, or a vectorcomprising the nucleic acid molecule, or an antibody drug conjugatecomprising the antibody or antigen binding fragment, or a compositioncomprising the antibody, antigen binding fragment, nucleic acidmolecule, vector, or antibody drug conjugate, and instructions for usingthe kit.
 33. A method of treating a subject with a tumor, comprising:selecting a subject with a tumor; and administering to the subject atherapeutically effective amount of the antibody or antigen bindingfragment of claim 1 under conditions sufficient to form an immunecomplex, wherein formation of the immune complex treats the tumor in thesubject.
 34. The method of claim 33, further comprising administering tothe subject a therapeutically effective amount of an anti-angiogenicagent or a chemotherapeutic agent.
 35. The method of claim 33, whereinthe antibody or antigen binding fragment is conjugated to a maytansinoidtoxin and/or an auristatin toxin.
 36. The method of claim 35, wherein:the maytansinoid toxin is DM1; and/or the auristatin toxin is MonomethylAuristatin E (MMAE) or Monomethyl Auristatin F (MMAF).
 37. The method ofclaim 33, wherein the tumor is colorectal, skin, lung, breast, prostate,or head and neck cancer.
 38. The method of claim 33, wherein treatingthe tumor comprises a reduction in tumor burden and/or a reduction intumor growth.
 39. The method of claim 33, wherein the tumor is in atumor microenvironment comprising a cell with increased cell surfaceexpression of TEM8.
 40. The method of claim 39, wherein the cell is anendothelial cell or a stromal cell.
 41. A method of detecting thepresence of a cell with cell-surface expression of TEM8 in a subject,comprising: contacting a cell from the subject with an effective amountof the antibody or antigen binding fragment of claim 1 under conditionssufficient to form an immune complex; and detecting the presence of theimmune complex on the cell from the subject, wherein the presence of theimmune complex on the cell from the subject indicates the presence of ancell with cell-surface expression of TEM8 in the subject.
 42. The methodof claim 41, wherein the contacting is in vivo.
 43. The method of claim41, wherein the contacting is in vitro.
 44. The method of claim 43,wherein the cell is in a biological sample from the subject.
 45. Themethod of claim 41, wherein the cell is an endothelial cell, a tumorstromal cell, and/or a tumor cell.
 46. The method of claim 41, whereinthe cell is an endothelial cell, and wherein detecting the presence ofthe endothelial cell expressing TEM8 in a subject detects pathologicalangiogenesis in the subject.
 47. The method of claim 41, wherein thecell is an endothelial cell, and wherein detecting the presence of theendothelial cell expressing TEM8 in the subject detects a tumor in thesubject.
 48. A method of decreasing the binding of Anthrax protectiveantigen to a cell, comprising: contacting the cell with an effectiveamount of the antibody or antigen binding fragment of claim 1 underconditions sufficient to form an immune complex, wherein formation ofthe immune complex decreases the binding of Anthrax protective antigento the cell.
 49. The method of claim 48, wherein contacting the cellwith an effective amount of the antibody or antigen binding fragmentcomprises administering a therapeutically effective amount of theantibody or antigen binding fragment to a subject comprising the cell.